MAGNETOCALORIC effects, CRYSTALLINE electric field, MAGNETIC entropy, MAGNETIC fields, MAGNETIC anisotropy, and CURIE temperature
We report on the large anisotropic magnetocaloric effect of PrAlSi, a ferromagnetic semimetal of current interest with a probable topologically nontrivial electronic structure. The maximum magnetic entropy change amounts to − Δ S M = 22.6 J / kg K near the Curie temperature T C = 17.8 K under a magnetic field change of μ 0 Δ H = 5 T along the magnetic easy c axis. A highly relevant feature is the small crystalline electric field splitting of the Pr 3 + (J = 4) multiplet, which appears to be comparable with the effective exchange interaction in the magnetic ordering. This leads to the full saturation moment of the Pr 3 + ion in small fields and an accumulation of magnetic entropy in the vicinity of the magnetic ordering. The weakly first-order nature of the ferromagnetic transition and the subsequent reentrant spin-glass transitions below T C are features further enhancing the magnetocaloric effect. Given the strong magnetic anisotropy, a large rotating magnetocaloric effect becomes achievable in this material. [ABSTRACT FROM AUTHOR]
ANDERSON localization, COLLOIDAL suspensions, ENERGY dissipation, CRYSTALLINE electric field, AMORPHOUS substances, and POLYDISPERSE media
In classical and quantum systems, order is of fundamental importance to many branches of science. Still, disorder is prevalent in our natural world. It manifests in various ways, and overcoming its limitations would open up exciting applications. In this work, we numerically show that disorder-induced Anderson localization can be mitigated and transmission systematically restored in random media through a self-organization process relying on energy dissipation. Under the scattering pressure produced by a driving optical field, a colloidal suspension composed of strongly polydisperse (i.e., random size) particles spontaneously assembles a Bloch-like mode with a broad transmission band. This mode displays a deterministic transmission scaling law that overcomes the statistical exponential decay expected in random media. This work demonstrates that, through the continuous dissipation of energy, amorphous materials can collectively synchronize with a coherent drive field and assemble a crystalline order. Self-organization, thus, offers a robust approach for addressing the physical limitations of disorder and immediately opens the door to applications in slow-light engineering and the development of "bottom-up" photonic materials. [ABSTRACT FROM AUTHOR]
MAGNETICS, MAGNETIC fields, EPITAXY, CRYSTALLINE electric field, MAGNETIC materials, POLYCRYSTALLINE semiconductors, and MAGNETORESISTANCE
As a candidate material for applications such as magnetic memory, polycrystalline antiferromagnets offer the same robustness to external magnetic fields, THz spin dynamics, and lack of stray fields as their single crystalline counterparts, but without the limitation of epitaxial growth and lattice matched substrates. Here, we first report the detection of the average Néel vector orientation in polycrystalline NiO via spin Hall magnetoresistance (SMR). Second, by applying strain through a piezo-electric substrate, we reduce the critical magnetic field required to reach a saturation of the SMR signal, indicating a change of the anisotropy. Our results are consistent with polycrystalline NiO exhibiting a positive sign of the in-plane magnetostriction. This method of anisotropy-tuning offers an energy efficient, on-chip alternative to manipulate a polycrystalline antiferromagnet's magnetic state. [ABSTRACT FROM AUTHOR]
MAGNETIC structure, MAGNETIC properties, CRYSTALLINE electric field, MAGNETIC moments, and NEUTRON diffraction
The magnetic properties and magnetic structures of Nd2TGe6 (T = Ni and Cu) were studied by magnetometric and neutron diffraction measurements. Both compounds have an orthorhombic crystal structure of the Ce2CuGe6-type and are antiferromagnetic with the Néel temperatures of 6.4 K (Nd2NiGe6) and 9.8 K (Nd2CuGe6). Based on the neutron diffraction data the magnetic structures were determined. In the investigated compounds all magnetic moments are localized on the Nd atoms and form a collinear commensurate magnetic structure with the magnetic unit cell equal to the crystal one. The moments are parallel to the b-axis (T = Ni) or to the c-axis (T = Cu). The obtained magnetic structures are discussed on the basis of competition between the RKKY-type interactions and influence of Crystalline Electric Field (CEF). [ABSTRACT FROM AUTHOR]
Anisimov, M., Samarin, N., Demishev, S., Bogach, A., Voronov, V., Shitsevalova, N., Levchenko, A., Filipov, V., and Glushkov, V.
Physics of the Solid State. Mar2021, Vol. 63 Issue 3, p414-419. 6p.
THERMOELECTRIC materials, RARE earths, CRYSTALLINE electric field, ELECTRIC field effects, SEEBECK coefficient, and THERMOELECTRICITY
Seebeck coefficient has been studied on the single crystals of metallic hexaborides RB6 (R = La, Pr, Nd, Gd) at temperatures of 2–300 K. The experiment has shown that the signal is limited by the values |S| ≤ 1.5 μV/K for all tested materials. The data obtained for the systems LaB6 and GdB6 were approximated by phonon drag contribution caused by quasi-local (Einstein) mode with characteristic temperatures ΘE(LaB6) ≈ 240 K and ΘE(GdB6) ≈ 180 K. On the contrary, the crystalline electric field effect induces the inversion between negative and positive types of thermoelectricity, which complicates the simulation of phonon drag in the case of PrB6 and NdB6. [ABSTRACT FROM AUTHOR]
Sato, H., Kubo, Y., Yoshioka, T., Tsuchiura, H., Mizuno, Y., Koike, K., Takahashi, K., and Kato, H.
AIP Advances. Feb2021, Vol. 11 Issue 2, p1-4. 4p.
SINGLE crystals, MAGNETIC moments, CRYSTALLINE electric field, CURIE temperature, HIGH temperatures, and MAGNETOCALORIC effects
Magnetization curves for Nd2Fe14B single crystals were measured between 300 K and 900 K. The saturation magnetization Ms along the  direction was found to be 2% to 4% smaller than that for the  direction, not only at 300 K but also up to the Curie temperature. We attributed this difference in Ms to the reduction of the Nd moment when forced to be aligned by external fields. Significant anisotropy was observed in the paramagnetic susceptibility χ up to 900 K. Based on the crystalline electric field parameters for Nd2Fe14B obtained by first-principles calculation, we calculated the magnetization and paramagnetic susceptibility χ. The difference in Ms and χ obtained from the calculation was in good agreement with the experiment. We found that the reduction rates for the Nd moments at 4f site are much smaller than that for the Nd moments at 4g site. This result therefore suggests a significant deterioration of local magnetic anisotropy at the Nd(4f) site even at elevated temperatures. [ABSTRACT FROM AUTHOR]
LATTICE theory, ION implantation, CRYSTALLINE electric field, RADIOISOTOPES, ELECTRON emission, CHANNELING (Physics), IONIC liquids, and CRYSTALLOGRAPHY
We report on the lattice location of low-fluence ion implanted 124In in single-crystalline 3C-SiC by means of the emission channeling technique using radioactive isotopes produced at the ISOLDE/CERN facility. In the sample implanted at room temperature to a fluence of 4 × 1012 cm−2, 60(9)% of the In atoms were found slightly displaced (0.12–0.20 Å) from substitutional Si sites, with the remainder occupying sites of low crystallographic symmetry, the so-called random sites. For 800 °C implantation, the substitutional In fraction increased to 72(8)% and the displacements from ideal substitutional Si sites were reduced to those expected for the lattice vibrations. These results, in terms of lattice location and disorder, are compared to those on In implanted group IV semiconductors silicon and diamond. [ABSTRACT FROM AUTHOR]