Observation of field induced anomalous quantum criticality in Ce0.6Y0.4NiGe2 compound

TL;DR

This study investigates how external magnetic fields induce anomalous quantum criticality in Ce0.6Y0.4NiGe2, revealing unusual fluctuations possibly caused by disorder from Y-substitution, contrasting with other compositions.

Contribution

It demonstrates the presence of anomalous quantum criticality and non-mean-field scaling behavior in Ce0.6Y0.4NiGe2 under magnetic fields, highlighting disorder-induced effects.

Findings

Magnetic frustration persists in Ce0.9Y0.1NiGe2

Quantum criticality is absent in Ce0.9Y0.1NiGe2 and Ce0.8Y0.2NiGe2

Ce0.6Y0.4NiGe2 shows anomalous quantum criticality with non-mean-field scaling

Abstract

We report the results of our investigation of magnetization and heat capacity on a series of compounds Ce1-xYxNiGe2 (x = 0.1, 0.2 and 0.4) under the influence of external magnetic field. Our studies of the thermodynamic quantity -dM/dT on these compounds indicate that magnetic frustration persists in Ce0.9Y0.1NiGe2, as also reported for the parent compound CeNiGe2. The weak signature of this frustration is also noted in Ce0.8Y0.2NiGe2, whereas, it is suppressed in Ce0.6Y0.4NiGe2. Heat capacity studies on Ce0.9Y0.1NiGe2 and Ce0.8Y0.2NiGe2 indicate the presence of a new magnetic anomaly at high field which indicates that quantum criticality is absent in these compounds. However, for Ce0.6Y0.4NiGe2 such an anomaly is not noted. For this later compound, the magnetic field (H) and temperature (T) dependence of heat capacity and magnetization obey H/T scaling above critical fields. However, the obtained scaling critical parameter ({\delta}) is 1.6, which is away from mean field value of 3. This deviation suggests the presence of unusual fluctuations and anomalous quantum criticality in these compounds. This unusual fluctuation may arise from disorderness induced by Y-substitution.