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SUMMARY:The internal magnetic field in a ferromagnetic compound Y$_2$Co$_{
 12}$P$_7$
DTSTART;VALUE=DATE-TIME:20220830T164000Z
DTEND;VALUE=DATE-TIME:20220830T170000Z
DTSTAMP;VALUE=DATE-TIME:20220826T121118Z
UID:indico-contribution-3753@indico.stfc.ac.uk
DESCRIPTION:Speakers: Kazuki Ohishi (CROSS Neutron Science and Technology 
 Center)\nVarious $\\mu^+$SR techniques have been widely used for studying 
 internal magnetic fields in assorted materials [1]\, such as\, antiferroma
 gnets\, spin-glasses\, paramagnets\, and superconductors. However\, for fe
 rromagnetic (FM) materials\, $\\mu^+$SR faces a difficulty in determining 
 the correct dipole field at the muon site $({\\bf H}_{\\rm dip})$ because 
 the internal magnetic field at the muon site in ferromagnets is expressed 
 by\; ${\\bf H}_{\\mu}={\\bf H}_{\\rm dip}~+~{\\bf H}_{\\rm L}~+~{\\bf H}_{
 \\rm hf}$\, where ${\\bf H}_{\\rm L}$ is the Lorentz field and ${\\bf H}_{
 \\rm hf}$ is the hyperfine field at the muon site. Therefore\, the muon si
 tes and the magnetic structure need to be apprehended for evaluating ${\\b
 f H}_{\\rm dip}$ but also the saturation magnetization for evaluating ${\\
 bf H}_{\\rm L}$ and the local spin density at the muon site for evaluating
  ${\\bf H}_{\\rm hf}$.\n\nConsidering the three contributions to ${\\bf H}
 _{\\rm \\mu}$ in the above equation\, a combined work with $\\mu^+$SR and 
 DFT calculations are needed to provide a reasonable estimate for the order
 ed magnetic moment of rare earth ($R$) ions in ${\\rm Nd}_2{\\rm Fe}_{14}{
 \\rm B}$ and related magnets [2]. Following upon this work\, we attempt to
  estimate the ordered magnetic moments of $R$ ions in cobalt-based FM mate
 rials\, $R_2{\\rm Co}_{12}{\\rm P}_7$ with such combined work. As a first 
 step\, a powder sample of $R_2{\\rm Co}_{12}{\\rm P}_7$ with $R={\\rm Y}$ 
 was measured with $\\mu^+$SR and three clear muon spin precession signals 
 below its Curie temperature ($T_{\\rm C}=151~$K) were found.\n\n[1] A. Yao
 uanc and P. D. de R$\\acute{\\rm e}$otier\, ``Muon Spin Rotation\, Relaxat
 ion\, and Resonance\, Application to Condensed Matter" (Oxford\, New York\
 , 2011).\n\n[2] J. Sugiyama et al.\, Phys. Rev. Material ${\\bf3}$\, 06440
 2 (2019).\n\nhttps://indico.stfc.ac.uk/event/53/contributions/3753/
LOCATION:Science and Technology Campus\, University of Parma
URL:https://indico.stfc.ac.uk/event/53/contributions/3753/
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