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E M Chudnovsky

Publications and source records attributed to E M Chudnovsky.

8 recordsLinked to original sources
PubMed2006

Electromagnetic radiation from vortex flow in Type-II superconductors.

We show that a moving vortex lattice, as it comes to a crystal edge, radiates into a free space the harmonics of the washboard frequency, omega(0)=2pi v/a, up to a superconducting gap, Delta/variant Planck's over 2pi. Here v is the velocity of the vortex lattice and a is the intervortex spacing. We compute radiation power and show that this effect can be used for the generation of terahertz radiation and for characterization of moving vortex lattices.

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PubMed2005

Field dependence of the electron spin relaxation in quantum dots.

The interaction of the electron spin with local elastic twists due to transverse phonons is studied. The universal dependence of the spin-relaxation rate on the strength and direction of the magnetic field is obtained in terms of the electron gyromagnetic tensor and macroscopic elastic constants of the solid. The theory contains no unknown parameters and it can be easily tested in experiment. At high magnetic field it provides a parameter-free lower bound on the electron spin relaxation in quantum dots.

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PubMed2005

Propagation of avalanches in Mn12-acetate: magnetic deflagration.

Local time-resolved measurements of fast reversal of the magnetization of single crystals of Mn12-acetate indicate that the magnetization avalanche spreads as a narrow interface that propagates through the crystal at a constant velocity that is roughly 2 orders of magnitude smaller than the speed of sound. We argue that this phenomenon is closely analogous to the propagation of a flame front (deflagration) through a flammable chemical substance.

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PubMed2004

Phonon superradiance and phonon laser effect in nanomagnets.

We show that the theory of spin-phonon processes in paramagnetic solids must take into account the coherent generation of phonons by the magnetic centers. This effect should drastically enhance spin-phonon rates in nanoscale paramagnets and in crystals of molecular nanomagnets.

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PubMed2003

Inertial mass of the Abrikosov vortex.

We show that a large contribution to the inertial mass of the Abrikosov vortex comes from transversal displacements of the crystal lattice. The corresponding part of the mass per unit length of the vortex line is M(l)=(m(2)(e)c(2)/64 pi alpha(2)mu lambda(4)(L))ln((lambda(L)/xi), where m(e) is the bare electron mass, c is the speed of light, alpha=e(2)/Planck's over 2 pi c approximately 1/137 is the fine structure constant, mu is the shear modulus of the solid, lambda(L) is the London penetration length, and xi is the coherence length. In conventional superconductors, this mass can be comparable to or even greater than the vortex core mass computed by Suhl [Phys. Rev. Lett. 14, 226 (1965)]].

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PubMed2002

Superradiance from crystals of molecular nanomagnets.

We show that crystals of molecular nanomagnets can exhibit giant magnetic relaxation due to the Dicke superradiance of electromagnetic waves. Rigorous theory is presented that combines superradiance with the Landau-Zener effect.

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PubMed2002

Reflectivity and microwave absorption in crystals with alternating intrinsic Josephson junctions.

We compute the frequency and magnetic field dependencies of the reflectivity R(omega) in layered superconductors with two alternating intrinsic Josephson junctions with different critical current densities and quasiparticle conductivities for the electric field polarized along the c axis. The parameter alpha describing the electronic compressibility of the layers and the charge coupling of neighboring junctions was extracted for the SmLa1-xSr xCuO (4-delta) superconductor from two independent optical measurements, the fit of the loss function L(omega) at zero magnetic field and the magnetic field dependence of the peak positions in L(omega). The experiments are consistent with a free electron value for alpha.

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