Quantum Oscillations, Colossal Magnetoresistance and Magnetoelastic Interaction in Bilayered Ca3Ru2O7

TL;DR

This study investigates the magnetic, transport, and structural properties of Ca3Ru2O7, revealing quantum oscillations, colossal magnetoresistance, and strong magnetoelastic interactions in a bilayered Mott-like system.

Contribution

It uncovers the interplay between lattice, magnetic, and electronic properties in Ca3Ru2O7, highlighting novel quantum oscillations and colossal magnetoresistance in a highly anisotropic Mott system.

Findings

Collapse of c-axis lattice parameter at TMI=48 K

Quantum oscillations observed in the nonmetallic state

Resistivity drops by three orders of magnitude under magnetic field

Abstract

We report magnetic and inter-plane transport properties of Ca3Ru2O7 at high magnetic fields and low temperatures. Ca3Ru2O7 with a bilayered orthorhombic structure is a Mott-like system with a narrow charge gap of 0.1eV. Of a host of unusual physical phenomena revealed in this study, a few are particularly intriguing: (1) a collapse of the c-axis lattice parameter at a metal-nonmetal transition, TMI (=48 K), and a rapid increase of TMI with low uniaxial pressure applied along the c-axis; (2) quantum oscillations in the gapped, nonmetallic state for 20 mK<T<6.5 K; (3) tunneling colossal magnetoresistance, which yields a precipitate drop in resistivity by as much as three orders of magnitude; (4) different in-plane anisotropies of the colossal magnetoresistance and magnetization. All results appear to indicate a highly anisotropic ground state and a critical role of coupling between lattice and magnetism. The implication of these phenomena is discussed.