Orbitally-driven Behavior: Mott Transition, Quantum Oscillations and Colossal Magnetoresistance in Bilayered Ca3Ru2O7

TL;DR

This study explores the complex magnetic, electronic, and structural behaviors of Ca3Ru2O7 under high magnetic fields, revealing anisotropic phase transitions, colossal magnetoresistance, and quantum oscillations linked to its rich interplay of degrees of freedom.

Contribution

It provides a comprehensive experimental characterization of Ca3Ru2O7's anisotropic phase diagram and uncovers new phenomena related to its spin, orbital, and lattice interactions under high magnetic fields.

Findings

First order metamagnetic transition for B||a

Colossal magnetoresistance for B||b

Quantum oscillations observed for B||c

Abstract

We report recent transport and thermodynamic experiments over a wide range of temperatures for the Mott-like system Ca3Ru2O7 at high magnetic fields, B, up to 30 T. This work reveals a rich and highly anisotropic phase diagram, where applying B along the a-, b-, and c-axis leads to vastly different behavior. A fully spin-polarized state via a first order metamagnetic transition is obtained for B||a, and colossal magnetoresistance is seen for B||b, and quantum oscillations in the resistivity are observed for B||c, respectively. The interplay of the lattice, orbital and spin degrees of freedom are believed to give rise to this strongly anisotropic behavior.