Dexin Li

Antiferromagnetic Resonance and Magnetic Structure of GdAs

Electron spin resonance measurements on single-crystal and powder of GdAs have been performed in the temperature range from 4.2 to 40 K and in the frequency range from 55 to 585 GHz to obtain micro...

Observation of cyclotron resonance in rare-earth monopnictides microwave region

Abstract We have directly determined the cyclotron effective masses of RX (R=La,Gd, X=As,Sb,Bi) by means of cyclotron resonance measurements at the frequency range between 56 and 190xa0GHz in the temperature range from 50 to 0.5xa0K. In addition to normal cyclotron resonance, two anomalous absorption lines are observed for the high-quality single crystal of LaSb, which shows quadratic behavior on the frequency–field diagram.

Cyclotron resonance of GdSb

Cyclotron resonance measurements on a single crystal of GdSb have been performed in the temperature range from 50 to 1.7 K, and the cyclotron effective mass of the carriers has been determined. The...

Magnetic Resonance of GdP

Electron spin resonance measurements on single-crystal of GdP have been performed in the temperature range from 5 to 40 K and in the frequency range from 50 to 109 GHz to obtain microscopic information about the magnetic structure. The results obtained indicate that GdP is an “easy-plane” antiferromagnet with the magnetic moment lying in the {111} plane below the Neel temperature (∼18 K). The estimated values of the exchange field and the out-of-plane anisotropy field are µ 0 H E =4.5 T and µ 0 H A =1.7 T, respectively.

NMR Study of a Heavy Fermion Compound YbAs

Nuclear magnetic resonance and relaxation studies on 75 As in an Yb-monopnictide YbAs have been carried out at temperatures down to 20 mK to clarify the magnetic properties of this compound from a microscopic point of view. A notable result is that the spin-lattice relaxation rate 1/ T 1 shows Fermi-liquid-like behavior given as ( T 1 T ) -1 =2.9 (s K) -1 below 0.2 K. The constant value of ( T 1 T ) -1 in YbAs is discussed using the Korringa relation for a single impurity model to compare with those in other heavy Fermion compounds. The NMR spectra between 0.4 K and 0.6 K indicate that the paramagnetic and the antiferromagnetically ordered regions coexist. From these results, it is found that YbAs is a heavy Fermion compound which undergoes an antiferromagnetic transition.

ESR and CR measurements of Gd monopnictides

Abstract In order to obtain information about the magnetic structure and the cyclotron effective mass (m CR ∗ ) of the carriers in Gd monopnictides, electron spin resonance (ESR) and cyclotron resonance (CR) measurements on single crystals have been performed in magnetic fields up to 25xa0T. The results indicate that GdP and GdAs are easy-plane antiferromagnets with the magnetic moment lying in the (1xa01xa01) plane below the Neel temperature. In GdAs, m CR ∗ varies from 0.45m0 to 0.48m0 depending on magnetic filed direction, suggesting that m CR ∗ is about two times larger than the masses estimated from the dHvA effect.

Magnetic resonance of GdBi

Abstract Electron spin resonance measurements on a single crystal of GdBi have been performed in the temperature range from 0.5 to 50xa0K. The absorption corresponding to g =2 of Gd 3+ -ion is observed at all temperatures except for 0.5xa0K. In addition, another absorption appears at 4.2xa0K and the resonance field shifts to lower field with decreasing temperature. This suggests that the hyperfine field arising from nuclear moments of Gd affects AFMR of GdBi.