Magnetoentropic Signatures of the Textured Metamagnetic Phase of an Antiferromagnetic Polar Metal: Ca₃Ru₂O₇

We report the magnetocaloric effect of a bilayered perovskite ruthenate Ca3Ru2O7 that has recently been recognized as an antiferromagnetic polar metal. The magnetic entropy change obtained from temperature dependence DC magnetization measurements shows peaks and valleys under field near metamagnetic transitions, enable us to map out thermodynamic field–temperature phase-diagram. area surrounded by boundaries agrees well with novel “metamagnetic texture” spin modulation observed small angle neutron scattering measurements. demonstrate thermodynamically equilibrium state is realized between spin-polarized states throughout transition in this