title: Magnetic transition temperatures follow crystallographic symmetry in samarium under high-pressures and low-temperatures.
abstract: Magnetic ordering temperatures in rare earth metal samarium (Sm) have been studied using an ultrasensitive electrical transport measurement technique in a designer diamond anvil cell to high-pressure up to 47 GPa and low-temperature to 10 K. The two magnetic transitions at 106 K and 14 K in the α-Sm phase, attributed to antiferromagnetic ordering on hexagonal and cubic layers respectively, collapse in to one magnetic transition near 10 GPa when Sm assumes a double hexagonal close packed (dhcp) phase. On further increase in pressure above 34 GPa, the magnetic transitions split again as Sm adopts a hexagonal-hP3 structure indicating different magnetic transition temperatures for different crystallographic sites. A model for magnetic ordering for the hexagonal-hP3 phase in samarium has been proposed based on the experimental data. The magnetic transition temperatures closely follow the crystallographic symmetry during α-Sm  →  dhcp  →  fcc/dist.fcc  →  hP3 structure sequence at high-pressures and low-temperatures.
authors.affiliation: Department of Mathematics, Saint Augustine's University, Raleigh, NC 27610, USA.
authors.forename: Craig R
authors.initials: CR
authors.lastname: Johnson
authors.forename: Georgiy M
authors.initials: GM
authors.lastname: Tsoi
authors.forename: Yogesh K
authors.initials: YK
authors.lastname: Vohra