Local character of the highest antiferromagnetic Ce-system CeTi{1-x}Sc{x} Ge

TL;DR

This study investigates the magnetic properties of CeTi{1-x}Sc{x}Ge alloys, revealing a transition from ferromagnetic to antiferromagnetic behavior with increasing Sc content, and attributes the high AFM temperature to RKKY interactions rather than electron hybridization.

Contribution

It provides detailed insights into the magnetic phase diagram of CeTi{1-x}Sc{x}Ge alloys and clarifies the local magnetic nature responsible for the high AFM temperature in CeScGe.

Findings

Transition from ferromagnetism to antiferromagnetism with increasing x

Absence of significant 4f electron hybridization at high Sc content

High AFM temperature attributed to RKKY inter-layer interactions

Abstract

The highest antiferromagnetic (AFM) temperature in Ce based compounds has been reported for CeScGe with Tn=47K, but its local or itinerant nature was not deeply investigated yet. In order to shed more light into this unusually high ordering temperature we have investigated structural, magnetic, transport and thermal properties of CeTi{1-x}Sc{x}Ge alloys within the range of stability of the CeScSi-type structure: 0.25<x<1. Along this concentration range, this strongly anisotropic system presents a complex magnetic phase diagram with a continuous modification of its magnetic behavior, from ferromagnetism (FM)for 0.25<x<0.50 (with 7K<Tc<16K) to AFM for 0.60<x<1 (with 19K<Tn<47K). The onset of the AFM phase is associated to a metamagnetic transition with a critical field increasing from H{cr}=0 at x~0.55 to ~6Tesla at x=1, coincident with an increasing contribution of the first excited crystal electric field doublet. At a critical point x{cr}=0.65 a second transition appears at Tl<Tn. In contrast to observations in itinerant systems like CeRh{2}Si{2} or CeRh{3}B{2}, no evidences for significant hybridization of the 4f electrons at large Sc contents were found. Therefore, the exceptionally large Tn of CeScGe can be attributed to an increasing RKKY inter-layer interaction as Sc content grows.