Structural Analysis of Novel Antiferromagnetic Material CeRu sub( 2)Al sub( 10) and Its Related Compounds under Pressure

We performed synchrotron X-ray studies of orthorhombic CeRu sub( 2)Al sub( 10) and its related compounds CeT sub( 2)Al sub( 10) (T = Fe, Os) and RRu sub( 2)Al sub( 10) (R = La, Yb, Lu). The results of the X-ray studies indicate that all of the compounds retain their orthorhombic crystal structures and that their lattice parameters all monotonically decrease with pressure; that is, no structural changes or distortions occur below 10 GPa within the experimental accuracy of this study. In addition, we evaluated the bulk moduli of the compounds, which are mainly affected by the transition metal in RT sub( 2)Al sub( 10) systems. All of the compounds exhibited crystal structures that were harder along the b-axis than along the a- or c-axes. Furthermore, anisotropic shrinkage induced a difference between the physical pressure of CeRu sub( 2)Al sub( 10) and the chemical pressure of Ce(Ru sub( 1...x)Fe sub( x)) sub( 2)Al sub( 10) (0 less than or equal to x less than or equal to 1). Thus, the physical properties of CeRu sub( 2)Al sub( 10) under pressure were observed to be strongly affected by crystal structure shrinkage along the a- and c-axes. (ProQuest: ... denotes formulae/symbols omitted.)