Observation of oscillatory magnetoresistance periodic in 1/B and B in Ca3Ru2O7

TL;DR

This study reports the discovery of both 1/B periodic and B periodic magnetoresistance oscillations in Ca3Ru2O7, revealing complex quantum phenomena linked to its electronic and magnetic properties at high magnetic fields.

Contribution

It is the first observation of B-periodic oscillations alongside traditional 1/B SdH oscillations in a Mott-like system, suggesting novel magnetic field coupling effects.

Findings

SdH oscillations are periodic in 1/B and depend on temperature and angle.

B-periodic oscillations persist up to 15 K and are linked to magnetic field coupling.

Oscillations reveal small Fermi surface pockets and exotic quantum effects.

Abstract

We report magnetoresistance oscillations in high magnetic fields, B, up to 45 T and over a wide range of temperature in the Mott-like system Ca3Ru2O7. For B rotating within the ac-plane, slow and strong Shubnikov-de Haas (SdH) oscillations periodic in 1/B are observed for T≤1.5 K in the presence of metamagnetism. These oscillations are highly angular dependent and intimately correlated with the spin-polarization of the ferromagnetic state. For B||[110], oscillations are also observed but periodic in B (rather than 1/B) which persist up to 15 K. While the SdH oscillations are a manifestation of the presence of small Fermi surface (FS) pockets in the Mott-like system, the B-periodic oscillations, an exotic quantum phenomenon, may be a result of anomalous coupling of the magnetic field to the t2g-orbitals that makes the extremal cross-section of the FS field-dependent.