Anisotropy of Superconducting MgB2 as Seen in Electron Spin Resonance and Magnetization Data

F. Simon; A. Jánossy; T. Fehér; F. Murányi; S. Garaj; L. Forró; C. Petrovic; S. L. Bud'ko; G. Lapertot; V. G. Kogan; P. C. Canfield

doi:10.1103/PhysRevLett.87.047002

Anisotropy of Superconducting MgB2 as Seen in Electron Spin Resonance and Magnetization Data

F. Simon, A. Jánossy, T. Fehér, F. Murányi, S. Garaj, L. Forró, C. Petrovic, S. L. Bud'ko, G. Lapertot, V. G. Kogan, P. C. Canfield

DOI 10.1103/PhysRevLett.87.047002 · Physical Review Letters

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Abstract

We observed the conduction electron spin resonance (CESR) in fine powders of MgB2 both in the superconducting and normal states. The Pauli susceptibility is χs=2.0×10−5emu/mole in the temperature range of 450 to 600K. The spin relaxation rate has an anomalous temperature dependence. The CESR measured below Tc at several frequencies suggests that MgB2 is a strongly anisotropic superconductor with the upper critical field, Hc2, ranging between 2 and 16T. The high-field reversible magnetization data of a randomly oriented powder sample are well described assuming that MgB2 is an anisotropic superconductor with Hc2ab/Hc2c≈6–9.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
MgB2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	39.2	Pressure not reported	unknown