Effects of pressure on the magnetic and crystallographic structure of Er5Si4

作     者：C. Magen L. Morellon Z. Arnold P. A. Algarabel C. Ritter M. R. Ibarra J. Kamarad A. O. Tsokol K. A. Gschneidner, Jr. V. K. Pecharsky 

作者机构：Materials and Engineering Physics Program Ames Laboratory Iowa State University Ames Iowa 50011-3020 USA and Department of Materials Science and Engineering Iowa State University Ames Iowa 50011-2300 USA 

出 版 物：《Physical Review B》 (Phys. Rev. B Condens. Matter Mater. Phys.)

年 卷 期：2006年第74卷第13期

页      面：134427-134427页

核心收录：

学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

摘      要：Extraordinary effects of the hydrostatic pressure on the crystallographic and magnetic properties of the Er5Si4 alloy have been examined by means of macroscopic (magnetization and linear thermal expansion) and microscopic (neutron powder diffraction) techniques. The high-temperature O(I)↔M crystallographic transformation (observed at Tt≅215K at atmospheric pressure) shifts to low temperatures at the unexpectedly high rate of dTt∕dP≅−30K∕kbar. In addition, the application of pressure induces an O(I) reentrance in the low-temperature ferromagnetic state of Er5Si4. The latter transformation (Tt2) is a reversible first-order-type structural phase transition shifting towards high temperature with pressure at a much lower rate of dTt2∕dP≅+6K∕kbar. This low-temperature O(I) crystal structure has a Curie temperature higher than that of the monoclinic polymorph, pointing out the importance of the interlayer covalentlike bonding to enhance the ferromagnetic interactions in these alloys. Above ∼6kbar, both structural transformations collapse, yielding a stable O(I) phase throughout the whole temperature range. In light of these experimental findings, a complete P−T magnetic-crystallographic phase diagram of Er5Si4 has been constructed.