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Title: Ac susceptibility study on {ital R}{sub 2}Fe{sub 14}B single crystals ({ital R}=Y, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm)

Journal Article · · Physical Review, B: Condensed Matter
; ; ;  [1];  [2]
  1. Institute for Experimental Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria)
  2. Van der Waals-Zeeman Institute, University of Amsterdam, Valckenierstraat 65, NL-1018 XE Amsterdam (The Netherlands)

The temperature dependence of the ac susceptibility {chi}={chi}{sup {prime}}+{ital i}{chi}{sup {double_prime}} has been measured on {ital R}{sub 2}Fe{sub 14}B single crystals with {ital R}=Y, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm as a function of temperature in the temperature interval from 4.2 to 300 K, as a function of the strength of the applied ac field (up to 800 A/m), as a function of frequency (ranging from 5 to 1000 Hz), as well as the dependence on the crystallographic orientation. A reversible rotation of magnetic moments, excited by applying the field perpendicular to the easy magnetization direction, is found to be the principal contribution to the susceptibility ({chi}{sup {prime}}). The energy loss is fairly small in this case ({chi}{sup {double_prime}}{approx_equal}0). When the external field is applied parallel to the easy magnetization direction, domain-wall movement is the main contribution to the susceptibility ({chi}{sup {prime}}) and to the energy loss ({chi}{sup {double_prime}}). For Nd{sub 2}Fe{sub 14}B, a peak in {chi}{sup {double_prime}}({ital T}) is detected at 135 K, the spin-reorientation temperature, in a 5 Hz field of 40 A/m applied along the [001] direction. This peak disappears upon increasing the frequency or upon changing the crystallographic orientation of the crystal. In addition, an anomaly in the temperature dependence of the susceptibility is detected around 220 K for {ital R}{sub 2}Fe{sub 14}B single crystals with {ital R}=Pr, Nd, Sm, Tb, and Dy. The presence of this anomaly depends on the crystallographic orientation. It can only be detected when the external field is applied parallel to the [001] direction. For all frequencies used, the temperature dependence of {chi}{sup {prime}} is completely different from that of {chi}{sup {double_prime}}. The {chi}{sup {prime}} values are nearly independent of the frequency in our measuring range from 5 to 1000 Hz. (Abstract Truncated)

OSTI ID:
385384
Journal Information:
Physical Review, B: Condensed Matter, Vol. 54, Issue 9; Other Information: PBD: Sep 1996
Country of Publication:
United States
Language:
English