United States

The ability of certain magnetic materials to change their entropy and/or temperature with the application and removal of a magnetic field (magnetocaloric effect, MCE) is a physical phenomenon that could lead to the realization of clean, energy-efficient heat pumping systems. We report a series of LaFe&lt;sub&gt;11.8&lt;/sub&gt;Si&lt;sub&gt;1.1&lt;/sub&gt;X&lt;sub&gt;0.1&lt;/sub&gt; compounds, where X = Al, Ga, and In, added in small concentrations, substantially reduce brittleness intrinsic to unsubstituted La(Fe&lt;sub&gt;1-x&lt;/sub&gt;Si&lt;sub&gt;x&lt;/sub&gt;)&lt;sub&gt;13&lt;/sub&gt;, while preserving or enhancing their giant MCEs [1]. Room temperature powder X-ray diffraction confirms formation of LaFe&lt;sub&gt;11.8&lt;/sub&gt;Si&lt;sub&gt;1.1&lt;/sub&gt;X&lt;sub&gt;0.1&lt;/sub&gt; adopting the NaZn&lt;sub&gt;13&lt;/sub&gt;-type structure as major phases, with ~10 to 15% of Î±Fe impurity. Surprisingly, relatively large amounts of Î±Fe do not deteriorate the magnetic field-induced entropy change (Î”S), yet the resultant alloys have much improved mechanical stability. The corresponding maximum Î”S are -18, -17, and -13 J kg&lt;sup&gt;-1 &lt;/sup&gt;K&lt;sup&gt;-1 &lt;/sup&gt;for X = In, Al, and Ga, respectively, in Î”H = 2 T in the vicinities of their respective Curie temperatures. The Curie temperatures of LaFe&lt;sub&gt;11.8&lt;/sub&gt;Si&lt;sub&gt;1.1&lt;/sub&gt;X&lt;sub&gt;0.1&lt;/sub&gt; materials can be increased to room temperature and above by hydrogenation, preserving the giant MCE. For example, a fully hydrogenated LaFe&lt;sub&gt;11.8&lt;/sub&gt;Si&lt;sub&gt;1.1&lt;/sub&gt;In&lt;sub&gt;0.1&lt;/sub&gt;H&lt;sub&gt;2.3&lt;/sub&gt; exhibits maximum Î”S close to -16 J kg&lt;sup&gt;-1 &lt;/sup&gt;K&lt;sup&gt;-1 &lt;/sup&gt;at T~344 K and Î”H =2 T.&lt;br/&gt;This work was supported by the Division of Materials Science and Engineering of the Office of Basic Energy Sciences of the U.S. DOE. Ames Laboratory is operated for the U.S. Department of Energy (DOE) by Iowa State University under Contract No. DE-AC02-07CH11358. AKP acknowledges the finanacial support from faculty startup fund from the Deanâ€™s Office, School of Arts and Sciences, SUNY Buffalo State.

MMM 2022

Tailoring mechanical properties and magnetocaloric effect in LaFe11.8Si1.2 zXzHy (X = Al, Ga, In)

The 15th Joint MMM-INTERMAG Conference (2022 Joint) is sponsored jointly by AIP Publishing and the IEEE Magnetics Society. Members of the international scientific and engineering communities interested in recent developments in fundamental and applied magnetism are invited to attend and contribute to the technical sessions. The technical program will include invited and contributed papers in oral and poster sessions, invited symposia, a plenary session, and an evening session, with about 1500 presentations overall. This Conference provides an outstanding opportunity for worldwide participants to meet their colleagues and collaborators and discuss developments in all areas of magnetism research.

The 2022 Joint Conference will offer both in-person and prerecorded on-demand content.

For tickets to the event, please register at the following link: https://magnetism.org/register

Please register for the Joint MMM-Intermag conference to join the event.

2022 Joint MMM-INTERMAG

This Conference provides an outstanding opportunity for worldwide participants to meet their colleagues and collaborators and discuss developments in all areas of magnetism research.

The ability of certain magnetic materials to change their entropy and/or temperature with the application and removal of a magnetic field (magnetocaloric effect, MCE) is a physical phenomenon that could lead to the realization of clean, energy-efficient heat pumping systems. We report a series of LaFe11.8Si1.1X0.1 compounds, where X = Al, Ga, and In, added in small concentrations, substantially reduce brittleness intrinsic to unsubstituted La(Fe1-xSix)13, while preserving or enhancing their giant MCEs [1]. Room temperature powder X-ray diffraction confirms formation of LaFe11.8Si1.1X0.1 adopting the NaZn13-type structure as major phases, with ~10 to 15% of Î±Fe impurity. Surprisingly, relatively large amounts of Î±Fe do not deteriorate the magnetic field-induced entropy change (Î”S), yet the resultant alloys have much improved mechanical stability. The corresponding maximum Î”S are -18, -17, and -13 J kg-1 K-1 for X = In, Al, and Ga, respectively, in Î”H = 2 T in the vicinities of their respective Curie temperatures. The Curie temperatures of LaFe11.8Si1.1X0.1 materials can be increased to room temperature and above by hydrogenation, preserving the giant MCE. For example, a fully hydrogenated LaFe11.8Si1.1In0.1H2.3 exhibits maximum Î”S close to -16 J kg-1 K-1 at T~344 K and Î”H =2 T. This work was supported by the Division of Materials Science and Engineering of the Office of Basic Energy Sciences of the U.S. DOE. Ames Laboratory is operated for the U.S. Department of Energy (DOE) by Iowa State University under Contract No. DE-AC02-07CH11358. AKP acknowledges the finanacial support from faculty startup fund from the Deanâ€™s Office, School of Arts and Sciences, SUNY Buffalo State.

technical paper

#### Welcome to the 67th Annual Conference on Magnetism and Magnetic Materials, MMM 2022!

The Conference was held from October 31 to November 4 and offers both in-person and on-demand content.

MMM 2022 is sponsored jointly by AIP Publishing and the IEEE Magnetics Society. Members of the international scientific and engineering communities interested in recent developments in fundamental and applied magnetism are invited to attend and contribute to the technical sessions. The technical program will include invited and contributed papers in oral and poster sessions, invited symposia, a tutorial, and several special sessions. This Conference provides an outstanding opportunity for worldwide participants to meet their colleagues and collaborators and discuss developments in all areas of magnetism research.

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Lanthanide dopants in oxide hosts provide excellent spin-photon interfaces for quantum technologies, including by mediating microwave to optical quantum transduction (converting a collective spin excitation to an optical excitation), and for quantum memories. The description of magnetic dipole transitions in lanthanides using model Hamiltonians principally relies on existing experimental fit parameters for terms in the Hamiltonian like the effect of the crystal field on the 4f elections. [1] Here, we deploy an ab initio extraction of crystal field parameters explored by Dadi Dai et al. [2] With ab initio, we extracted crystal field parameters in Er defects in hosts like Y2O3, and in combining the extracted crystal field parameters with the effective operator Hamiltonian approach we were able to compare the theoretical crystal field energy correction with experimental values directly and obtained a relatively good match. In further studies weâ€™re exploring a more systematic prediction of crystal field levels to pave the path for a wide search of lanthanide doped spin-photon systems. We acknowledge funding from NSF DMR-1921877.

Ab initio Crystal Field Splittings for Lanthanide Dopants in Oxide Materials for Quantum Information

Interfacial properties of two-dimensional (2D) van der Waals material/magnetic material heterostructures are crucial for applications in spintronics and valleytronics. Inspired by the recent observation of room temperature ferromagnetic ordering in 2D MoS2 induced by the ferrimagnetic yttrium iron garnet (YIG) and the antiferromagnetic exchange coupling between MoS2 and YIG in a MoS2 / YIG heterostructure [1], investigation into the proximity-mediated spin properties of such heterostructures has become a topic of global interest. Nonetheless, a full understanding of the magnetic proximity effect (MPE) and its temperature and magnetic field evolution in these systems is lacking. In this study, we have used biphase iron oxide (Fe3O4 + Fe2O3) as the magnetic layer and the MPE has been probed in Pt / Tungsten Disulfide / biphase iron oxide heterostructures through a comprehensive investigation of their magnetic and transport properties using magnetometry, transverse susceptibility, four-probe resistivity, and anomalous Hall effect (AHE) measurements. Density functional theory (DFT) calculations are performed to complement the experimental findings. We find that the presence of monolayer Tungsten Disulfide flakes reduces the magnetization of biphase iron oxide and hence the total magnetization of Pt / Tungsten Disulfide / biphase iron oxide above the Verwey transition temperature of Fe3O4 (TV). However, the enhanced magnetization is achieved at T < TV. In the latter case, a comparative analysis of the transport properties of the Pt / Tungsten Disulfide / biphase iron oxide heterostructure and the Pt / biphase iron oxide heterostructructures from the AHE measurements reveals a ferromagnetic coupling at the Tungsten Disulfide / biphase iron oxide interface. Our study forms the foundation for understanding MPE-mediated interfacial properties and paves a new pathway for designing 2D van der Waals material/magnet heterostructures for spin-based device applications 

**References** (1) Tsai, S. P.; Yang, C. Y.; Lee, C. J.; Lu, L. S.; Liang, H. L.; Lin, J. X.; Yu, Y. H.; Chen, C. C.; Chung, T. K.; Kaun, C. C.; Hsu, H. S.; Huang, S. Y.; Chang, W. H.; He, L. C.; Lai, C. H.; Wang, K. L. Room-Temperature Ferromagnetism of Single-Layer MoS2 Induced by Antiferromagnetic Proximity of Yttrium Iron Garnet. Advanced Quantum Technologies 2021, 4, 2000104. https://doi.org/10.1002/qute.202000104.

Proximity Enhanced Anomalous Hall Transport in Biphase Iron Oxide/Tungsten Disulfide Heterostructures

Spin-orbit torque characterization techniques generally require Hall cross that generally demands lithography resources and time. As the interest in exploring materials for improved SOT performance surges, an efficient technique to characterize SOT efficiencies with minimal processes, equipment, and time is highly desirable. Here, we demonstrate a lithography-free technique to determine the spin-orbit torque efficiency in perpendicular magnetic anisotropy ferromagnetic heterostructure. By utilizing a customized fzour-point probe in a rhombus geometry, harmonic Hall measurement was performed on a blanket films of Pt/Co/Ti structure to characterize the spin-orbit torque efficiency. Due to the non-uniform current distribution across the blanket film, a correction factor is experimentally evaluated using the ratio of the damping-like field measured on the blanket film to that of a fabricated Hall device with identical material heterostructure. Additionally, this correction factor is analytically derived and experimentally shown to be determined by the configuration of the probes and is independent of the structure material. Our measurement reveals that by performing a single calibration process for the particular set of probes, the same correction factor was validated on a second ferromagnetic heterostructure, Ti/Pt/Co/Ta hence it can be applied to other SOT films stack measurements. Our four-probe harmonic Hall technique provides an alternative and swift way for SOT investigations by eliminating multiple lithography processes necessary in conventional approaches.

Blanket Film Spin Orbit Torque Characterization via Four Probe Measurement

Spin-orbit coupling (SOC) plays a vital role in spin-to-charge interconversion in heavy metal (HM)-ferromagnet (FM) bilayer structures [1]. Spin pumping is an efficient method to generate pure spin current by the precessional motion of magnetization, which transfers angular momentum to HM. The efficiency of spin pumping is quantified by an interfacial parameter called spin-mixing conductance (g↓↑). Electrical detection of spin current is possible via inverse spin Hall effect (ISHE) which converts spin current into charge current. The efficiency of spin-to-charge interconversion is quantified by spin Hall angle (θSH) [2]. The θSH of heavy metal highly depends on its crystalline phase and the effect of the seed layer on the phase of HMs is largely overlooked. Here, we report the effect of seed permalloy (Ni80Fe20, Py) layer thickness on the Tantalum (Ta) and Tungsten (W) crystalline phase and its θSH. We have observed a structural phase transition in Ta as a function of seed layer thickness (tPy) affecting the θSH of the Ta layer. Due to strain at the interface between crystalline Py and Ta, Ta exhibits a mixed-phase (α+β) on the seed permalloy layer when tPy > 12 nm. However, Ta nucleates as α-Ta on Py with tPy < 8 nm, Py does not exhibit prominent crystalline nature. The phase transition of Ta is primarily attributed to strain at the Py/Ta interface which is not observed in both Py(tPy)/W(10) and Co40Fe40B20 (tCFB)/Ta(18) bilayer structure. Ferromagnetic resonance (FMR) based spin pumping shows that effective damping is enhanced for all samples. The maximum g↓↑ of 10.1×1018 m-2 is observed for Si/Py(20)/Ta(18) and the minimum value of 7.9×1018 m-2 for Si/Py(8)/Ta(18) which corresponds to (α+β)-phase of Ta and α-phase of Ta, respectively. The estimated θSH for (α+β)-Ta is 0.15 ± 0.009, which is higher than α-Ta. The combined effect of symmetry breaking and low longitudinal resistance are the primary reason for the high g↓↑ and θSH. Our systematic study provides an insight into Ta phase transition via seed layer thickness and gives an alternative route for tuning [3]. 
**References*** [1] A. Brataas, Y. V. Nazarov, and G. E. W. Bauer, Finite-Element Theory of Transport in Ferromagnet–Normal Metal Systems, Phys. Rev. Lett. 84, 2481 (2000).
[2] Y. Tserkovnyak, A. Brataas, and G. E. W. Bauer, Nonlocal Magnetization Dynamics in Ferromagnetic Heterostructures, Rev. Mod. Phys. 77, 1375 (2005).
[3] K. Sriram, A. Haldar, and C. Murapaka, Effect of Seed Layer Thickness on the Ta Crystalline Phase and Spin Hall Angle, Nanoscale 13, 19985 (2021). 
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Effect of seed layer thickness on Ta crystalline phase and spin Hall angle

Soft magnetic composites(SMCs) consist of ferromagnetic particles, in the micrometer-range which are embedded in an electrically insulating material, in order to reduce the eddy-currents in the high-frequency regime. We want to utilize numerical simulations in order to optimize such materials in terms of power-loss and permeability. The problem one faces is that the samples have macroscopic sizes, however if one would want to resolve these materials on the micro-scale, it would limit the total simulation size to a few micrometers. Introducing a truncated geometry or cut-off would also not solve this problem as demagnetization effects would come into play for any finite sized sample. However due to the torus-like shape of the sample, the magnetic flux closure reduces the strayfield to zero. To overcome these issues we developed and implemented our own method for calculating the micromagnetic strayfield with periodic boundary conditions(PBCs)[1]. PBCs allow us to simulate an infinite sample and therefore avoid the demagnetization effects. A complete magnetic simulation framework including PBCs will be presented with which the spatially- and time-resolved magnetization response to an external field is simulated. The model will be validated among other things by reproducing experimental setups that have successfully reduced the power-loss of SMCs. Suetsuna et al.[2] have shown that the power-loss reduces by roughly half when the sample is exposed to a magnetic field during annealing, because an aligned anisotropy direction is induced. This was replicated in the simulation and as can be seen in figure 1 the simulated power-loss Pm decreases by half when an aligned anisotropy is applied, without altering the relative permeability mur. 

**References** 
[1] Bruckner, Florian, et al. "Strayfield calculation for micromagnetic simulations using true periodic boundary conditions." Scientific Reports 11.1 (2021): 1-8.
[2] Suetsuna, Tomohiro, et al. "Soft magnetic composite containing magnetic flakes with in-plane uniaxial magnetic anisotropy." Journal of Magnetism and Magnetic Materials 473 (2019):
416-421. 

![](https://s3.eu-west-1.amazonaws.com/underline.prod/uploads/markdown_image/1/image/1c066203e20a987f28c178a793a3e69b.png) 

Fig. 1 Powerloss Pm and permeability mur were calculated from hysteresis simulations utilizing the SMC model with aligned and random anisotropy.

Simulation of Soft Magnetic Composites with Periodic Strayfield Calculation

Non-collinear antiferromagnetic orders are of strong interest in the fields of spintronic, topological magnetism and multiferroicity [1]. However, the magnetic imaging of these materials is particularly challenging due to their zero net magnetization. The main goal of this work is to achieve the fully vectorial reconstruction of a non-collinear magnetic order, by the combination of Resonant X-ray Magnetic Scattering (RXMS) [2] and Coherent Diffraction Imaging (CDI) [3] . Dy epitaxial films exhibiting an antiferromagnetic helical phase and strong X-ray magnetic scattering at the Dy L3 edge [4] are interesting candidates. The micro-patterning of Dy nanofilms (top-down approach) is required to synthetize model micro-objects and to efficiently implement this technique. We present the results of the microfabrication process and the full structural and magnetic characterization of the Dy Âµ-disks. The high crystalline quality of the Dy(0001) epitaxial films is maintained after the optical lithography and Ion Beam Etching. X-ray diffraction (Fig.1) indicates moderate decrease in the coherence length (10%) and increase in mosaÃ¯city (17%) in 2mm diameter disks compared with continuous films. A fcc phase however tends to form, most likely due to hydrogenation during the patterning process . SQUID measurements and Resonant X-Ray Magnetic Scattering (BM28-ESRF) confirm the occurrence of the helical phase in the Dy Âµ-disks, with similar NÃ©el and Curie temperatures as in continuous films. (002-t) magnetic satellites reveal that helical turn angles in the patterned samples do not differ significantly from those observed in epitaxial films [5] (Fig. 2). The role of the buffer layer (Nb or Nb/Y) on the crystal quality and the presence of crystalline defects is also carefully investigated, since structural speckles in CDI have to be avoided for measurements and proper analysis of the magnetic contributions.

Development of Dy µ disks for coherent imaging of helimagnetic domains

LaFe13-x-yMxSiyN3 compounds (M = Mn) were synthesized by flowing ammonia over intermetallic precursors at 623 K for 4 hours. The nitrides were characterized by room temperature powder X-ray diffraction, magnetic thermogravimetry (mTGA), differential scanning calorimetry (DSC), and magnetization measurements. The nitrides derived from Si-poor (y â‰¤ 3) cubic intermetallics retain the NaZn13-type crystal structure and the lattice parameters, a, of the synthesized trinitrides increase by ~3 % compared to the precursors. The nitrogenation increases ferromagnetic ordering temperature by approximately 200 K when compared with the corresponding nitrogen-free NaZn13-type phases, but unlike those of the latter, TCs of the nitrides are independent of the Fe/Si ratio. Partial substitution of Fe with Mn lowers TC of the trinitride similarly to the non-nitrogenated precursors. The magnetic ordering transitions in the nitrides are broad, resulting in rather weak magnetocaloric effects peaking at -2.0 J/Kg K for a 0 to 5 T magnetic field change. The nitrides are stable below 750 K, but they begin to lose nitrogen above this temperature, fully decomposing above 1050 K. Ames Laboratory is operated for the U.S. Department of Energy (DOE) by Iowa State University under Contract No. DE-AC02-07CH11358. This work was supported by the Division of Materials Science and Engineering of the Office of Basic Energy Sciences of the U.S. DOE.

Synthesis and magnetic properties of LaFe13 x

Body Magnetic particle imaging (MPI) is a technique to visualize magnetic nanoparticles with high spatial and temporal resolutions based on nonlinear magnetization response.1
One of major challenges toward clinical MPI system is how to implement low ac excitation fields. For brain MPI particularly,2 a 24 kHz excitation field intensity with amplitude over 3.5
mT may induce peripheral nerve stimulation on human head.3 However, low-field MPI scenario degrades spatial resolution since the detected signal has no harmonic components but high
contamination from the excitation fields. Previously, we applied 1 MHz excitation field to elevate signal-to-noise ratio of receive coil.4 To further decontaminate magnetization signal
spectrally, we used magnetoresistive (MR) sensor to transform monotone signal into harmonic-rich one and reconstructed phantom image from odd harmonic components.5 Extensively,
MR sensor can be used to map quasistatic stray field of magnetic nanoparticles.6
Here, we will report the use of a 6×6 channels array of TDK Nivio xMR sensors to detect sub-pT magnetic signal and obtain its spatial distribution. While each sensor is operated at 5 V,
signal processing circuit rises its sensitivity to 20 mV/ pT at 10 kHz with 0.25 pT noise level. We used a 40-turns coil with 1 mm diameter and 5 mm length to represent magnetic moment.
The distance between MR sensor and the coil (dx) was 250 mm [Fig. 1(a)]. From Fig. 1(b), MR sensor recognizes magnetic signal from mini coil fed with a 10 kHz ac current. Magnetic
field detected by the sensor (Hd) is linear with coil input current (i). Furthermore, we simultaneously recorded the signals from 36 sensor channels to map at 200 Hz. We set dx=50 mm to
obtain high contrast showing coil position relative to the array. From Fig. 2, the change in field polarity is observable from frames (i), (ii), (iii), and (iv) with channel c16 as reference. This
result highlights usability of MR sensor array for low-field MPI system. 

**References:** 

1. B. Gleich and J. Weizenecker, Nature, 435, 1214 (2005). 
2. M. Graeser, F. Thieben and T. Knopp, Nat. Commun., 10, 1936 (2019). 
3. A. A. Ozaslan, M. Utkur and E. U. Saritas, Int. J. Mag. Part. Imag., 8, 2203028 (2022). 
4. S. B. Trisnanto and Y. Takemura, Phys. Rev. Appl., 14, 064065 (2020). 
5. S. B. Trisnanto, T. Kasajima and Y. Takemura, Appl. Phys. Express, 14, 095001 (2021). 
6. S. B. Trisnanto, T. Kasajima and Y. Takemura, J. Appl. Phys. 131, 224902 (2022). 

![](https://s3.eu-west-1.amazonaws.com/underline.prod/uploads/markdown_image/1/image/b5b3087b0d83f3fdd69c1125bdafc2e0.png)

Sub pT oscillatory magnetometric system using magnetoresistive sensor array for a low

There has been a need for rapid screening of people infected virus including with COVID-19 or influenza. Virus detection methods using magnetic harmonics of magnetic nanoparticles (MNPs) with superparamagnetism has been reported [1, 2]. In this study, we report the detection of influenza virus based on magnetic second harmonic signals [3], and the detection sensitivity was 100 pg/mL. Figure 1 shows the developed system for virus detection. The excitation coil generated AC magnetic fields of amplitude of 6.6 mT with 1 kHz and the detection coil detect the second harmonic signals of MNPs under DC magnetic field of 6.6 mT. The measurement of the magnetization response of MNPs completed in one minute. The samples contained MNPs (Nanomag-D, average diameter 20 nm, 5 mg/mL, 9.24Ã—1012 particles) coated with protein-A, with which antibodies (Nucleoprotein InA245). Antigens (Influenza A virus) bound to the antibodies by antigen-antibody reaction. Figure 2 shows the relation between the second harmonic signal normalized by the fundamental signal R2/R0 and the third harmonic signal normalized by the fundamental signal R3/R0 with five different antigen concentrations (0, 103, 105, 107, 109 antigens). R2/R0 was about 2.3 times larger than R3/R0. This result indicates that the detection of viruses using the second harmonic signal has a larger detectable range of the number of antigens. In addition, the value of R2/R0 significantly reduce at 104 antigens (Fig. 2(a)). This result indicate that we can detect 104 antigens (100 pg/mL). In the future, we aim to achieve detection sensitivity of the PCR method (1 pg/mL) by investigating the optimal detection coil shape, excitation frequency, and concentration of MNPs for virus detection.

Rapid Virus Detection using Magnetic Second Harmonics of Superparamagnetic Iron Oxide Nanoparticles

The proximity-coupling of a chiral non-collinear antiferromagnet (AFM) (1,2) with a singlet superconductor allows spin-unpolarized singlet Cooper pairs to be converted
into spin-polarized triplet pairs (3,4) thereby enabling non-dissipative, long-range spin
correlations (3,4). The mechanism of this conversion derives from fictitious magnetic
fields that are created by a non-zero Berry phase (5) in AFMs with non-collinear
atomic-scale spin arrangements (1,2). In this invited talk, I will describe our recent achievement of long-ranged lateral Josephson supercurrents through an epitaxial thin
film of the triangular chiral AFM Mn3Ge (6). The Josephson supercurrents in this
chiral AFM decay by approximately 1–2 orders of magnitude slower than would be
expected for singlet pair correlations (3,4) and their response to an external magnetic field reflects a clear spatial quantum interference. Given the long-range supercurrents
present in both single- and mixed-phase Mn3Ge, but absent in a collinear AFM IrMn, our results pave away for the topological generation of spin-polarized triplet pairs (3,4) via Berry phase engineering (5) of the chiral AFMs.

If time permits, I will also present our experimental realization of spin-triplet supercurrent spin-valves (SVs) (7,8) in chiral antiferromagnetic Josephson junctions (JJs) and a direct current superconducting quantum interference device (dc SQUID), the latter of which reveals an intriguing 0-to-π phase transition (8) on top of the SV response to out-of-Kagome plane magnetic fields. 

**References:** 
(1) Nakatsuji, S. et al. Nature 527, 212 (2015), 
(2) Nayak, A. K. et al. Sci. Adv. 2, e1501870 (2016), 
(3) Linder, J. & Robinson, J. W. A. Nat. Phys. 11, 307 (2015), 
(4) Eschrig, M. Rep. Prog. Phys. 78, 104501 (2015), 
(5) Xiao, D., Chang, M.-C. & Niu, Q. Rev. Mod. Phys. 82, 1959 (2010), 
(6) Jeon, K.-R. et al, Nat. Mater. 20, 1358 (2021), 
(7) Banerjee, N. et al. Nat. Comm. 5, 4771 (2014), 
(8) Glick, J. A. et al. Sci. Adv. 4, eaat9457 (2018).

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Ab initio Crystal Field Splittings for Lanthanide Dopants in Oxide Materials for Quantum Information

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