Critical two and threespin correlations in EuS: An investigation with polarized neutrons
Abstract
The critical magnetic scattering has been investigated in EuS by means of smallangle scattering with polarized neutrons using an inclined magnetic field geometry, allowing the determination of threespin correlation functions. Two contributions to the critical magnetic scattering I{sub {sigma}}(q)=I{sup {up_arrow}}(q)+I{sup {down_arrow}}(q) and {delta}I(q)=I{sup {up_arrow}}(q)I{sup {down_arrow}}(q) were studied for temperatures near T{sub C}=16.52 K. The I{sup {up_arrow}}(q) and I{sup {down_arrow}}(q) are the scattering intensities for the incident neutron beam polarized along ({up_arrow}) and opposite ({down_arrow}) to the magnetic field. The symmetric contribution, namely I{sub {sigma}}(q), comes from the pairspin correlation function. The scattering intensity is well described by the OrnsteinZernike expression I{sub {sigma}}(q)=A(q{sup 2}+{kappa}{sup 2}){sup 1}, where {kappa}={xi}{sup 1} is the inverse correlation length of the critical fluctuations. The correlation length {xi} obeys the scaling law {xi}=a{sub 0}{tau}{sup {nu}}, where {tau}=(TT{sub C})/T{sub C} is the reduced temperature, a{sub 0}=0.17 nm, and {nu}=0.68{+}0.01. The difference contribution {delta}I(q) is caused by the threespin chiral dynamical spin fluctuations that represent the asymmetric part of the polarization dependent scattering. The q dependence of {delta}I(q) follows closely 1/q{sup 2}. {delta}I(q) depends on the temperature as {tau}{sup {nu}} with {nu}=0.64{+}0.05. The exponents {nu} as determined by means of the static measurements by {xi} and the dynamic measurementsmore »
 Authors:
 Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg 188300 (Russian Federation)
 TUMunchen, Garching (Germany)
 GKSS Forschungszentrum, 21502 Geesthacht (Germany)
 Publication Date:
 OSTI Identifier:
 20787749
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 72; Journal Issue: 21; Other Information: DOI: 10.1103/PhysRevB.72.214423; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALGEBRA; ASYMMETRY; CHIRALITY; CORRELATION FUNCTIONS; CORRELATIONS; EUROPIUM SULFIDES; FACTORIZATION; FERROMAGNETIC MATERIALS; FLUCTUATIONS; GEOMETRY; MAGNETIC FIELDS; NEUTRON BEAMS; NEUTRON DIFFRACTION; NEUTRONS; POLARIZATION; SCALING LAWS; SMALL ANGLE SCATTERING; SPIN
Citation Formats
Grigoriev, S.V., Metelev, S.V., Maleyev, S.V., Okorokov, A.I., Boeni, P., Georgii, R., Lamago, D., Eckerlebe, H., and Pranzas, K. Critical two and threespin correlations in EuS: An investigation with polarized neutrons. United States: N. p., 2005.
Web. doi:10.1103/PHYSREVB.72.2.
Grigoriev, S.V., Metelev, S.V., Maleyev, S.V., Okorokov, A.I., Boeni, P., Georgii, R., Lamago, D., Eckerlebe, H., & Pranzas, K. Critical two and threespin correlations in EuS: An investigation with polarized neutrons. United States. doi:10.1103/PHYSREVB.72.2.
Grigoriev, S.V., Metelev, S.V., Maleyev, S.V., Okorokov, A.I., Boeni, P., Georgii, R., Lamago, D., Eckerlebe, H., and Pranzas, K. Thu .
"Critical two and threespin correlations in EuS: An investigation with polarized neutrons". United States.
doi:10.1103/PHYSREVB.72.2.
@article{osti_20787749,
title = {Critical two and threespin correlations in EuS: An investigation with polarized neutrons},
author = {Grigoriev, S.V. and Metelev, S.V. and Maleyev, S.V. and Okorokov, A.I. and Boeni, P. and Georgii, R. and Lamago, D. and Eckerlebe, H. and Pranzas, K.},
abstractNote = {The critical magnetic scattering has been investigated in EuS by means of smallangle scattering with polarized neutrons using an inclined magnetic field geometry, allowing the determination of threespin correlation functions. Two contributions to the critical magnetic scattering I{sub {sigma}}(q)=I{sup {up_arrow}}(q)+I{sup {down_arrow}}(q) and {delta}I(q)=I{sup {up_arrow}}(q)I{sup {down_arrow}}(q) were studied for temperatures near T{sub C}=16.52 K. The I{sup {up_arrow}}(q) and I{sup {down_arrow}}(q) are the scattering intensities for the incident neutron beam polarized along ({up_arrow}) and opposite ({down_arrow}) to the magnetic field. The symmetric contribution, namely I{sub {sigma}}(q), comes from the pairspin correlation function. The scattering intensity is well described by the OrnsteinZernike expression I{sub {sigma}}(q)=A(q{sup 2}+{kappa}{sup 2}){sup 1}, where {kappa}={xi}{sup 1} is the inverse correlation length of the critical fluctuations. The correlation length {xi} obeys the scaling law {xi}=a{sub 0}{tau}{sup {nu}}, where {tau}=(TT{sub C})/T{sub C} is the reduced temperature, a{sub 0}=0.17 nm, and {nu}=0.68{+}0.01. The difference contribution {delta}I(q) is caused by the threespin chiral dynamical spin fluctuations that represent the asymmetric part of the polarization dependent scattering. The q dependence of {delta}I(q) follows closely 1/q{sup 2}. {delta}I(q) depends on the temperature as {tau}{sup {nu}} with {nu}=0.64{+}0.05. The exponents {nu} as determined by means of the static measurements by {xi} and the dynamic measurements (using the chirality) are in excellent agreement with each other, demonstrating the internal consistency of the theory and the experiment. Therefore, our results confirm the principle of the critical factorization, which is known as PolyakovKadanoffWilson operator algebra.},
doi = {10.1103/PHYSREVB.72.2},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 21,
volume = 72,
place = {United States},
year = {Thu Dec 01 00:00:00 EST 2005},
month = {Thu Dec 01 00:00:00 EST 2005}
}

We have defined and have calculated the twobody and threebody spincorrelative probabilities to study spin correlations. Condensates of spin2 atoms are chosen as examples; however, the underlying concept is general. These probabilities can directly relate to the experimental data. Therefore, they can be used to discriminate the spin structures and to clarify the interactions of various systems.

Spinpolarized hydrogen confined in three and twodimensions
Experimental efforts to produce a Bose Einstein condensed (BEC) gas of spinpolarized atomic hydrogen have been intensely pursued since 1980. Initial efforts studied hydrogen in contact with superfluid helium surfaces. In order to avoid the limiting wall recombination a static magnetic trap was developed which utilizes magnetic barriers to isolate atoms from the van der Wals walls. In this approach traps can be filled to about 10{sup 14} atoms/cm{sup 3} for which the critical temperature is in the region of 2030 {mu}K. However, approaching BEC conditions, a new instability dominates the behavior. The authors have developed a new type ofmore »