Two-Dimensional Spin Dynamics in the Itinerant Ferromagnet LaCoPO Revealed by Magnetization and ${}^{31}$P-NMR Measurements

Abstract

We have performed magnetization and ${}^{31}$P-NMR measurements on the itinerant ferromagnet LaCoPO (Curie temperature $T_{\mathrm{Curie}}\sim 44$ K) with a layered structure in order to investigate spin dynamics in the paramagnetic state. The linear scaling between the Knight shift $K$ at the P site and the bulk susceptibility $\chi$ above $T_{\mathrm{Curie}}$ indicates that the P nucleus is suitable for investigating magnetic properties. The temperature and magnetic field dependences of the nuclear spin-lattice relaxation rate divided by the temperature $1/T_{1}T$ at the P site show characteristic features of itinerant ferromagnets, such as ZrZn${}_2$ and Y(Co${}_{1-x}$Al${}_x$)${}_2$. In addition, the relationship between $1/T_{1}T$ and $\chi$ above $T_{\mathrm{Curie}}$ suggests that ferromagnetic fluctuations possess a two-dimensional (2D) characteristic. The present data show that LaCoPO is a unique ferromagnet, where the 2D fluctuations anticipated from the crystal structure are predominant down to almost $T_{\mathrm{Curie}}$.

5 pages, 6 figures, to appear in J. Phys. Soc. Jpn, Vol.78, No.11

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Cited by in corpus (6)

• Common effect of chemical and external pressures on the magnetic properties of RECoPO (RE = La, Pr)
• Field tuned critical fluctuations in YFe2Al10: Evidence from magnetization, 27Al (NMR, NQR) investigations
• Large Magnetoresistance Effects in $Ln$CoAsO with a Ferromagnetic-Antiferromagnetic Transition
• Spectroscopic Study of ${}^{75}$As and ${}^{139}$La NMR on Layered Structure Ferromagnet LaCoAsO
• Study of electron spin dynamics in grain aligned LaCoPO: an itinerant ferromagnet
• Anisotropic spin-fluctuations in SmCoPO revealed by 31^P NMR measurement