Metamagnetism

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

A theoretical and experimental study of magnetism in Gd2In

Abstract: We present detailed theoretical calculations and careful experiments to elucidate the magnetic properties of Gd2In Our calculations suggest that Gd2In is a rather unique system where both localized 4f electrons as well as itinerant 5d electrons all originating from Gd are responsible for its novel magnetic properties with hardly any role of In s, p electrons A careful analysis of the magnetization and magnetoresistance data as a function of field revealed that the magnetic behavior of Gd2In may be divided into three distinct regions We argue with the aid of first principles electronic structure calculations that these three regions originate due to the different response of the localized 4f and itinerant 5d electrons of Gd upon application of the magnetic field We show that in addition to the Gd 4f electrons, the Gd 5d electrons are also important for the metamagnetic behavior of Gd2In These results establish the important role of Gd 5d electrons in the magnetic properties of Gd2In that so far only r

Enhancement of ferromagnetism by nickel doping in the ‘112’ cobaltite EuBaCo2O5.50

Abstract: Study of the ordered oxygen deficient perovskite EuBaCo2−xNixO5.50 shows that the doping of cobalt sites by nickel induces a strong ferromagnetic component at low temperature in the antiferromagnetic matrix of EuBaCo2O5.50. This system indeed exhibits phase separation, i.e. it consists of ferromagnetic domains embedded in the antiferromagnetic matrix of EuBaCo2O5.50. Besides, a magnetic transition is observed for the first time at 40 K in the undoped and nickel-doped phases, which can be attributed to the ferromagnetic ordering of the Eu3+ moments below this temperature. Moreover sharp ultra magnetization multisteps are observed below 5 K, characteristic of the motion of domain walls in a 'strong pinning' system and very different from any metamagnetic transition.

Orbital and spin correlations in Ca2-xSrxRuO4: A mean field study

Abstract: The alloy Ca2-x Sr x RuO4 exhibits a complex phase diagram with peculiar magnetic metallic phases. In this paper some aspects of this alloy are discussed based on a mean field theory for an effective Kugel-Khomskii model of localized orbital and spin degrees of freedom. This model results from an orbital selective Mott transition which in the three-band system localized two orbitals while leaving the third one itinerant. Special attention is given to the region around a structure quantum phase transition at $ x \approx 0.5 $ where the crystal lattice changes from tetragonal to orthorhombic symmetry while leaving the system metallic. This transition yields, a change from ferromagnetic to antiferromagnetic spin correlations. The complete mean field phase diagram for this transition is given including orbital and spin order. The anisotropy of spin susceptibility, a consequence of spin-orbit coupling and orbital correlation, is a tell-tale sign of one of these phases. In the predominantly antiferromagnetic phase we describe a metamagnetic transition in a magnetic field and show that coupling of the itinerant band to the localized degrees of freedom yields an anomalous longitudinal magnetoresistance transition. Both phenomena are connected with the evolution of the ferromagnetic and antiferromagnetic domains in the external magnetic field and agree qualitatively with the experimental findings.