Metamagnetism

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

Giant magnetoresistance effects in intermetallic compounds (invited)

Abstract: Giant magnetoresistance (GMR) effects are observed in several classes of bulk magnetic materials. The resistance changes at metamagnetic transitions connected with reorientation of 4f moments are only moderate due to the relatively weak coupling of the 4f and conduction electrons. Much larger GMR effects can be achieved by mechanisms involving the d states (RhFe, RCo2), though the most spectacular resistance variations are connected with metamagnetic transitions in U‐intermetallic antiferromagnets. This phenomenon can be interpreted as due to Fermi surface gapping (due to magnetic superzones) and/or due to spin‐dependent scattering in analogy with magnetic multilayers.

Metamagnetic Phase Transitions in FeTiO 3

Abstract: Magnetic susceptibilities and magnetization isotherms have been measured for single crystal FeTiO 3 The susceptibility parallcl to the c -axis has a large and sharp peak at T N =580±03 K, while the perpendicular susceptibility is almost independent of temperature below T N Magnetization isotherm at 42 K with fields applied along the c -axis exhibits a typical metamagnetic transition at H c =803±01 kOe, being the first observation of metamagnetism in 3 d transition metal oxides The transition is of the first order up to about 35 K, above which it is of the second order The experimental data are well reproduced by molecular field calculations with the best fit parameters of the anisotropy field H A =150 kOe, the ferromagnetic intrasublattice exchange interaction of 2 z 1 J 1 =285 K, and the antiferromagnetic intersublattice interaction of 2 z 2 J 2 =-667 K

Quantum bicriticality in the heavy-fermion metamagnet YbAgGe.

Abstract: Bicritical points, at which two distinct symmetry-broken phases become simultaneously unstable, are typical for spin-flop metamagnetism. Interestingly, the heavy-fermion compound YbAgGe also possesses such a bicritical point (BCP) with a low temperature T(BCP)≈0.3 K at a magnetic field of μH(BCP)≈4.5 T. In its vicinity, YbAgGe exhibits anomalous behavior that we attribute to the influence of a quantum bicritical point that is close in parameter space yet can be reached by tuning T(BCP) further to zero. Using high-resolution measurements of the magnetocaloric effect, we demonstrate that the magnetic Gruneisen parameter ΓH indeed both changes sign and diverges as required for quantum criticality. Moreover, ΓH displays a characteristic scaling behavior but only on the low-field side H≲H(BCP), indicating a pronounced asymmetry with respect to the critical field. We speculate that the small value of T(BCP) is related to the geometric frustration of the Kondo lattice of YbAgGe.

Composition dependence of magnetocaloric effect in Sm1-xSrxMnO3 (x = 0.3-0.5)

Abstract: We investigated magnetic and magnetocaloric properties in Sm1-xSrxMnO3 (x = 0.30-0.5). We report a magnetic field driven first-order metamagnetic transition in the paramagnetic state in x = 0.4 and 0.5 and a second-order transition in x = 0.3. The highest magnetic entropy (-Sm = 6.2 J/kgK for H = 5 T at T = 125 K) that occurs in x = 0.4 is associated with the metamagnetic transition resulting from the field-induced growth and coalescence of ferromagnetic nano clusters preexisting in the paramagnetic state. Our results suggest that manganites with intrinsic nanoscale phase separation can be exploited for magnetic refrigeration.