G. V. Shcherbakov

Magnetism in disordered magnetic Fe82−xNixCr18

The zero field μSR-method has been used to study the magnetism in the disordered magnetic alloy Fe82−xNixCr18 near the three-critical, pointx=25. The dynamic and static local field distributions are analyzed. The difference between spin-glass states obtained either from the paramagnetic or after the double transition is discussed.

Temperature dependence of the quadruple interaction and the diffusion of muonium atoms in α-quartz

The results of an experimental investigation of the quadrupole interaction of muonium atom in-quartz in the temperature region 75–300 K are presented. It is show that the observed temperature dependence of the quadrupole interaction parameters is fully determined by the diffusion of muonium.

μSR study of antiferromagnetic phase-transitions in dysprosium and holmium

It is shown that the temperature dependence Λ (T) of the muon spin relaxation rate in the paramagnetic state of dysprosium and holmium does not reveal any singularity at T−>TN′ where TN is the Neel temperature. This result contradicts the assumption of the second-order antiferromagnetic phase-transition in these metals and is in good agreement with computations within the renormalization group method.

The MSR-investigation of antiferromagnetic phase transitions in erbium

The muon spin relaxation rateΛ (T) in an orientated polycrystalline sample of erbium constructed of large monocrystals has been measured for temperatures 20 <T<300 K. It has been shown that theΛ (T) for erbium is bounded from above asT → TN, whereTN=84.4 K is the Néel temperature. This fact may be explained by assuming that atT=TN erbium undergoes a weak phase-transition of the first order.

Investigation of magnetic ordered state in YBa2Cu3O6+x (0.06<X<0.32) bY μSR

The magnetic state properties have been studied in YBa2Cu3O6+x with (0.06<x<0.32). The increase of muon depolarization rate was found below 100K in all samples. In contrast to the previousμSR-studies two precession signals with the frequencies close to 4MHz was observed at T=20÷80K. Possible reasons of the phenomena at T<100K are discussed.

μSR study of Cu10Zr7

It is shown that temperature dependences Λ(T) of dipole relaxation rate of the positive muon spin in crystalline and amorphous states of Cu10Zr7 are approximately the same over the temperature interval 20–300 K. this fact points out approximately identical close-order structure of crystalline and amorphous states of Cu10Zr7 alloy.

Quantum diffusion of muons in bismuth

A muon spin relaxation rate in a super-pure sample of bismuth has been measured. The experimental data and the theory of coherent diffusion in crystalline lattices with shifted levels are compared.

Observation of a Gabay–Toulouse line in Fe0.6Mn0.4Pt3 alloy

It was shown that in the frustrated ferromagnet belonging to the group of structurally ordered Fe_x Mn1-x Pt3 alloys the temperature of the transition from the ferromagnetic state to the asperomagnetic state followed a Gabay–Toulouse line.

Research on magnetic phase transitions in frustrated fcc-iron alloys by μSR-method

It was shown that in the Heisenberg frustrated antiferromagnetic FexNi80−xCr20 alloys with the concentrations (x) near critical point the following succession of transitions is observed under cooling: paramagnet — collinear antiferromagnet- non-collinear antiferromagnet (antiasperomagnet) — reentrant spin glass. For the frustrated ferromagnetic (FexMn1−x)Pt3 alloys the existence of slow relaxation processes was shown which are the result of dynamic crossover from the ferromagnetic state to an asperomagnetic one.

μSR study of the superconducting state Nb3Al

By means of the uSR method, the critical temperature Tk=(17.41 0.05) K and the inhomogenety of the internal magnetic field in Nb3Al in the mixed state for two values of external magnetic fields H=62 Oe and H=285 Oe over the temperature range 9–17 K were measured.