Magneto-elastic coupling and competing entropy changes in substituted CoMnSi metamagnets

Abstract

We use neutron diffraction, magnetometry and low temperature heat capacity to probe giant magneto-elastic coupling in CoMnSi-based antiferromagnets and to establish the origin of the entropy change that occurs at the metamagnetic transition in such compounds. We find a large difference between the electronic density of states of the antiferromagnetic and high magnetisation states. The magnetic field-induced entropy change is composed of this contribution and a significant counteracting lattice component, deduced from the presence of negative magnetostriction. In calculating the electronic entropy change, we note the importance of using an accurate model of the electronic density of states, which here varies rapidly close to the Fermi energy.

11 pages, 9 figures. Figures 4 and 6 were updated in v2 of this preprint. In v3, figures 1 and 2 have been updated, while Table II and the abstract have been extended. In v4, Table I has updated with relevant neutron diffraction data

References in corpus (6)

• Magnetocaloric materials: the search for new systems
• Mixed Magnetism for Refrigeration and Energy Conversion
• Giant magneto-elastic coupling in a metallic helical metamagnet
• Structurally driven metamagnetism in MnP and related Pnma compounds
• Designed Metamagnetism in CoMnGe_{1-x}P_{x}
• Ultrasonic studies of the magnetic phase transition in MnSi

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• Wide temperature span of entropy change in first-order metamagnetic MnCo1-xFexSi
• Basics of the magnetocaloric effect
• Complex magnetic phase diagram of metamagnetic MnPtSi
• Coherent spin rotation-induced zero thermal expansion in MnCoSi-based spiral magnets