Metamagnetism

About: Metamagnetism is a research topic. Over the lifetime, 2023 publications have been published within this topic receiving 38108 citations.

Metamagnetism of Methylamine Chrome Alum

Abstract: Methylamine chrome alum shows an antiferromagnetic ordering below 0.015°K–0.02°K and it is known that this ordering results from the magnetic dipole-dipole interaction among the chromic ions. The present paper investigates, on the basis of the molecular field approximation, the phenomenon of transition below the Neel point from the antiferromagnetic state to the paramagnetic state caused by an applied field, at constant temperature or at constant entropy. Depending on the direction of the applied field relative to the crystalline axes and also on the shape of sample, different behaviours of the transition are obtained. For a spherical sample three are studied, namely, the cases of H //[111], H //[100] and H //[10\bar1], and for an infinitely long sample two cases, i.e., the axis of the sample and H are both parallel to either [111] or [100]. In Appendix is given a summary of the previous theoretical study by Kanamori. Motizuki and Yosida of the same kind of antiferro-paramagnetic transition in two-sublatt...

Magnetic-Field-Induced Phenomena in the Paramagnetic Superconductor UTe$_{2}$

Abstract: We present magnetoresistivity measurements on the heavy-fermion superconductor UTe$_{2}$ in pulsed magnetic fields $\mu_0H$ up to 68~T and temperatures $T$ from 1.4 to 80~K. Magnetic fields applied along the three crystallographic directions $\mathbf{a}$ (easy magnetic axis), $\mathbf{b}$, and $\mathbf{c}$ (hard magnetic axes), are found to induce different phenomena - depending on the field direction - beyond the low-field suppression of the superconducting state. For $\mathbf{H}\parallel\mathbf{a}$, a broad anomaly in the resistivity is observed at $\mu_0H^*\simeq10$~T and $T = 1.4$~K. For $\mathbf{H}\parallel\mathbf{c}$, no magnetic transition nor crossover are observed. For $\mathbf{H}\parallel\mathbf{b}$, a sharp first-order-like step in the resistivity indicates a metamagnetic transition at the field $\mu_0H_m \simeq 35$~T. When the temperature is raised signature of first-order metamagnetism is observed up to a critical endpoint at $T_{CEP}\simeq7$~K. At higher temperatures a crossover persists up to 28~K, i.e., below the temperature $T_\chi^{max} = 35$~K where the magnetic susceptibility is maximal. A sharp maximum in the Fermi-liquid quadratic coefficient $A$ of the low-temperature resistivity is found at $H_m$. It indicates an enhanced effective mass associated with critical magnetic fluctuations, possibly coupled with a Fermi surface instability. Similarly to the URhGe case, we show that UTe$_{2}$ is a candidate for field-induced reentrant superconductivity in the proximity of $H_m$.

“Chemical Metamagnetism”: From Antiferromagnetic PrCo2P2 to Ferromagnetic Pr0.8Eu0.2Co2P2 via Chemical Compression

Abstract: Magnetic properties of itinerant magnets depend on peculiarities of their electronic band structure. Introduction of Eu into PrCo2P2 pushes the material from antiferromagnetism to ferromagnetism. The change is due to a strong chemical compression that “squeezes out” electrons from the localized Eu 4f levels into the delocalized Co 3d subband.

Existence of Fine Structure inside Spin Gap in CeRu2Al10

Abstract: We investigate the magnetic field effect on the spin gap state in CeRu 2 Al 10 by measuring the magnetization and electrical resistivity. We found that the magnetization curve for the magnetic field H ∥ c shows a metamagnetic-like anomaly at H * ∼4 T below T 0 =27 K, but no anomaly for H ∥ a or H ∥ b . A shoulder of the electrical resistivity at T s ∼5 K for I ∥ c is suppressed by applying a longitudinal magnetic field above 5 T. Many anomalies are also found in the magnetoresistance for H ∥ c below ∼5 K. The obtained magnetic phase diagram consists of at least two or three phases below T 0 . These results strongly indicate the existence of a fine structure on a low-energy side in a spin gap state with an excitation energy of 8 meV, which has recently been observed in inelastic neutron scattering experiments.