Magnetism of Eu and Dy under Extreme Pressures Wenli Bi Advanced - PowerPoint PPT Presentation

Magnetism of Eu and Dy under Extreme Pressures Wenli Bi Advanced Photon Source, Argonne National Laboratory, Argonne COMPRES (University of Illinois at Urbana-Champaign) 1

High pressure SMS experiment setup Ruby%system% 21# 2

Basic Mössbauer parameters of 151 Eu 151 R. Röhlsberger, Nuclear Condensed Ma/er Physics with Synchrotron Radia8on , (Springer Berlin Heidelberg, Berlin, Heidelberg, 2005), Ch. 2, p. 25. 3

Hyperfine interactions of 151 Eu quadrupole interaction in Eu magnetic interaction in Eu 4

Simulations of M ӧ ssbauer spectra of Eu Simulated Mössbauer data in 151 Eu Time domain Energy domain 5

Experimental lab Mössbauer data in 151 Eu QS = 33 mm/s H = 26.5 T Shaken et al., Phys. Rev. Lett. 55, 312 (1985). Malik et al.,Phys. Rev. Lett. 55, 316 (1985). Cohen et. al., Phys. Rev. 184, 263 (1969). Barrett and D. Shirley, Phys. Rev. 131, 123 (1963).

Eu 2+ : (4 f 7 , J= 7/2) Eu 3+ : (4 f 6 , J= 0) Data taken from Mössbauer effect data center, http://www.medc.dicp.ac.cn/ 7

8 Courtesy of E. E. Alp

Pressure induced magnetic transition in Eu (4 f 7 5 d 0 6 s 2 J = 7/2 ) 8 GPa 2 10 0 10 4 10 12.3 GPa 2 10 0 10 4 10 17.5 GPa 2 10 0 10 4 10 47 GPa 2 10 counts 4 10 59 GPa magnetic 2 10 0 10 4 10 67 GPa 2 10 0 10 2 81 GPa 10 0 10 2 93 GPa 10 sc 0 10 2 101 GPa 10 0 10 20 40 60 80 -60 -40 -20 0 20 40 60 time (ns) velocity (mm/s) Bi et al., Phys. Rev. B . 93 , 184424 (2016).

No significant valence change in Eu experiment ab-initial data Röhler, Phys. B+C 144, 27 (1986). Bi et al., Phys. Rev. B . 93 , 184424 (2016).

Basic Mössbauer parameters of 161 Dy (4 f 9 5 d 1 6 s 2 , J = 15/2 ) 151 R. Röhlsberger, Nuclear Condensed Ma/er Physics with Synchrotron Radia8on , (Springer Berlin Heidelberg, Berlin, Heidelberg, 2005), Ch. 2, p. 25. 11

Magnetism in Dy Doniach model T RKKY ~ J 2 T k ~ exp( ⎮ J ⎮ ) Lim et al., Phys. Rev. B 91 , 045116 (2015). Samudrala et al., High Press. Res. 34 , 266 (2014).

H hf = 550 T 77"K" ~"0.4"ns" ~"5"ns" ~"0.1"ns" velocity (cm/s) G.J."Bowden,"D.S.P."Bunbury,"and"J.M."Williams,"Proc."Phys."Soc."91,"612"(1967)." 40 cm/s spliMng (0.12 ns), beyond the APD Qme resoluQon (1 ns). As a result, only the inner spliMng can be resolved from Qme domain spectrum. 13

Dy SMS simulation with different detector time resolution 0.01 ns H hf = 574 T 0.1 ns 1 ns counts 0 20 40 60 80 100 120 time (ns) 14

Y. V Shvyd’ko et al., Europhys. LeX. 56, 309 (2001). 15

Magnetic hyperfine field in Eu (6 s 2 4 f 7 5 d 0 ) H H H H = + + hf C CE n at#4.2#K# H C H CE H n H C :$ insensi,ve#to#volume#change.# Elmegid$and$Kaindl,$hyperfine$interac7ons$4,$420$(1978).$ Klein,$Wortmann$and$Kalvius,$18,291$(1976);$$ H CE $ and# H n :$ dependent#of#volume#(pressure)# Nowik,$Dunlap$and$Wernick,$Phys.$Rev.$B$8,$238$(1973).$ #change.#RKKY#interac,on.# Hüfner$and$Wernick,$Phys.$Rev.$173,$448$(1968)$ $ $ 16