Copper Titanates: A Family of Magneto-Quantum Paraelectrics

TL;DR

This paper explores a family of copper titanates exhibiting magneto-quantum paraelectric behavior, revealing hidden quantum paraelectricity in CCTO through Li-doping, and characterizing their low-temperature dielectric properties.

Contribution

It identifies and characterizes a family of copper titanates with shared low-temperature quantum paraelectric and magnetic properties, revealing hidden quantum paraelectricity in CCTO via Li-doping.

Findings

SCTO and CLCTO follow Barrett-form quantum paraelectric behavior above TN.

CCTO's behavior is masked by thermally-activated site disorder.

Li-doping reveals hidden quantum paraelectricity in CCTO with increased dielectric constant.

Abstract

A magneto-quantum-paraelectric family is emergent from the shared low-temperature characteristics of representative SrCu3Ti4O12 (SCTO), CaCu3Ti4O12 (CCTO), and Ca0.9Li0.1Cu3Ti4O12 (CLCTO) antiferro-tilted/A1/4A'3/4BO3-structures. Above their magnetic ordering temperatures TN, dielectric permittivity of SCTO and CLCTO follow typical quantum paraelectric Barrett-form unambiguously, whereas in CCTO, this behaviour is masked by the huge {\epsilon}'-step, born of thermally-activated site-antisite (Ca/Cu) disorder. The hidden quantum paraelectricity in CCTO is revealed with Li-doping at Ca-site, by considerable temperature-scale-upshift of the colossal dielectric constant (CDC) anomaly.