Title page for etd-0526115-133008


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URN etd-0526115-133008
Author Tien-yu Wei
Author's Email Address No Public.
Statistics This thesis had been viewed 5586 times. Download 418 times.
Department Physics
Year 2014
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Effect of Zn substitution on the Skyrmion phase in Cu2OSeO3
Date of Defense 2015-06-06
Page Count 65
Keyword
  • vortex
  • phase diagram
  • Cu2OSeO3
  • skyrmion
  • doping effect
  • Abstract There is a considerable interest growing on the discovery of new magnetic state in the field of condensed matter physics. Skyrmion state (A-phase) is one kind of such novel magnetic phase where spin forms the vortex-like ordering. This phenomena was initially discover in metallic MnSi and later realized in insulating Cu2OSeO3. This unusual magnetic ordering appeared in a finite temperature and magnetic field window. In this present work we are studying the influence of nonmagnetic element substitution on the skyrmion phase of the Cu2OSeO3 system. Polycrystalline (Cu1-xZnx)2OSeO3 ( x = 0, 0.01, 0.02, 0.04, 0.06, 0.08, 0.10, 0.15, 0.20) samples were synthesized using solid state reaction method and characterized by XRD, and magnetic measurements. The crystal structure belongs to the non-centrosymmetric cubic space group P213. Variation of lattice constant with Zn doping follows the Vegard’s law which signifies the fairly successful substitution of Zn in place of Cu up to x≦0.20. The Curie temperature and the value of magnetization decrease with higher Zn doping indicate the ferrimagnetic ordering is gradually suppressed. Moreover, we have notice another magnetic phase for the doping level 0.02<x<0.20, whose magnetic transition also shifted to low temperature for higher Zn doping. The H-T magnetic phase diagrams of all the samples from ac susceptibility by scanning magnetic field (χˈac-H) have been established with increasing Zn doping. The explanations for the observations of doping effects on the A-phase of skyrmion Cu2OSeO3 will be discussed.
    Advisory Committee
  • Hsiung Chou - chair
  • Jim-Long Her - co-chair
  • Jiunn-Yuan Lin - co-chair
  • Hung-Duen Yang - advisor
  • Files
  • etd-0526115-133008.pdf
  • Indicate in-campus at 1 year and off-campus access at 1 year.
    Date of Submission 2015-06-29

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