TY - JOUR
T1 - Local electromagnetic properties of magnetic pnictides
T2 - A comparative study probed by NMR measurements
AU - Majumder, M.
AU - Ghoshray, K.
AU - Ghoshray, A.
AU - Pal, A.
AU - Awana, V. P.S.
PY - 2013/5/15
Y1 - 2013/5/15
N2 - 75As and 31P NMR studies are performed in PrCoAsO and NdCoPO respectively. The Knight shift data in PrCoAsO indicate the presence of an antiferromagnetic interaction between the 4f moments along the c axis in the ferromagnetic state of Co 3d moments. We propose a possible spin structure in this system. The 75As quadrupolar coupling constant, νQ, increases continuously with decrease of temperature and is found to vary linearly with the intrinsic spin susceptibility, Kiso. This indicates the possibility of the presence of a coupling between charge density and spin density fluctuations. Further, the 31P NMR Knight shift and spin-lattice relaxation rate (1/T1) in the paramagnetic state of NdCoPO indicate that the differences of LaCoPO and NdCoPO from SmCoPO are due to the decrement of the interlayer separation and not due to the moments of the 4f electrons. The nuclear spin-lattice relaxation time (T1) in NdCoPO shows weak anisotropy at 300 K. Using the self-consistent renormalization (SCR) theory of itinerant ferromagnets, it is shown that in the ab plane, the spin fluctuations are three-dimensional ferromagnetic in nature. From SCR theory the important spin-fluctuation parameters (T0, T A, ) are evaluated. The similarities and dissimilarities of the NMR results in As and P based systems with different rare earths are also discussed.
AB - 75As and 31P NMR studies are performed in PrCoAsO and NdCoPO respectively. The Knight shift data in PrCoAsO indicate the presence of an antiferromagnetic interaction between the 4f moments along the c axis in the ferromagnetic state of Co 3d moments. We propose a possible spin structure in this system. The 75As quadrupolar coupling constant, νQ, increases continuously with decrease of temperature and is found to vary linearly with the intrinsic spin susceptibility, Kiso. This indicates the possibility of the presence of a coupling between charge density and spin density fluctuations. Further, the 31P NMR Knight shift and spin-lattice relaxation rate (1/T1) in the paramagnetic state of NdCoPO indicate that the differences of LaCoPO and NdCoPO from SmCoPO are due to the decrement of the interlayer separation and not due to the moments of the 4f electrons. The nuclear spin-lattice relaxation time (T1) in NdCoPO shows weak anisotropy at 300 K. Using the self-consistent renormalization (SCR) theory of itinerant ferromagnets, it is shown that in the ab plane, the spin fluctuations are three-dimensional ferromagnetic in nature. From SCR theory the important spin-fluctuation parameters (T0, T A, ) are evaluated. The similarities and dissimilarities of the NMR results in As and P based systems with different rare earths are also discussed.
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U2 - 10.1088/0953-8984/25/19/196002
DO - 10.1088/0953-8984/25/19/196002
M3 - Article
C2 - 23604391
AN - SCOPUS:84876900998
SN - 0953-8984
VL - 25
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
IS - 19
M1 - 196002
ER -