Anisotropic paramagnetism of monoclinic Nd2Ti2O7 single crystals

TL;DR

This study explores the anisotropic magnetic properties and specific heat behavior of Nd2Ti2O7 single crystals, highlighting the roles of crystal field effects and exchange interactions in their magnetic response.

Contribution

It isolates the contributions of exchange and crystal field interactions to Weiss temperature and characterizes the Schottky ground state in Nd2Ti2O7.

Findings

Exchange interactions are ferromagnetic.

Crystal field contributes a large negative Weiss temperature.

Specific heat reveals a two-level Schottky ground state.

Abstract

The anisotropic paramagnetism and specific heat in Nd2Ti2O7 single crystals are investigated. Angular dependence of the magnetization and Weiss temperatures show the dominant role of the crystal field effect in the magnetization. By incorporating the results from the diluted samples, contributions to Weiss temperature from exchange interactions and crystal field interactions are isolated. The exchange interactions are found to be ferromagnetic, while the crystal field contributes a large negative part to the Weiss temperature, along all three crystallographic directions. The specific heat under magnetic field reveals a two-level Schottky ground state scheme, due to the Zeeman splitting of the ground state doublet, and the g-factors are thus determined. These observations provide solid foundations for further investigations of Nd2Ti2O7.