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Title: Optical tests for broken time-reversal symmetry in the cuprate superconductors

Abstract

Optical measurements have been made on YBa[sub 2]Cu[sub 3]O[sub 7] and Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8] to search for both spontaneous Faraday rotation (in transmission) and spontaneous Kerr rotation (reflection). The observation of these magneto-optical effects near Tc would be a clear indication that the superconductivity in the cuprate superconductors can be explained by a theory which predicts broken time-reversal (T) symmetry. In particular, the [open quotes]any on[close quotes] model of these materials predicts that T symmetry will be broken spontaneously as the material is cooled. The magneto-optical effects are expected to be quite small compared to the birefringence of the material. A method has been developed that uses a fiber-optic Sagnac interferometer to search for the magneto-optic signal. Incident upon the samples are two counter-propagating circularly polarized beams, whose electric fields have opposite time dependence. The interferometer detects Faraday or Kerr rotation by measuring the difference in phase between these beams after they have interacted with the sample. Because it is immune to birefringence in the sample, this method is superior to simply analyzing the polarization state of a single beam. Transmission experiments at 1060 nm wavelength were done with a modified fiber-optic gyroscope (a type of Sagnac interferometer).more » The nonreciprocal phase shift observed in the cuprates was less than the sensitivity (2 [mu]rad). A 670 nm interferometer was constructed to look for these effects in the visible portion of the spectrum, where other researchers have witnessed unusual polarization effects.Both reflection and transmission measurements at this wavelength indicate there are no magneto-optic effects to a sensitivity of 5 [mu]rad. This technique has been applied successfully to study ferromagnetic phase transitions in films of EuO and Gd.« less

Authors:
Publication Date:
Research Org.:
Stanford Univ., CA (United States)
OSTI Identifier:
6988327
Resource Type:
Miscellaneous
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CUPRATES; FARADAY EFFECT; KERR EFFECT; HIGH-TC SUPERCONDUCTORS; ANYONS; BARIUM OXIDES; BISMUTH OXIDES; CALCIUM OXIDES; EUROPIUM OXIDES; GADOLINIUM; INTERMETALLIC COMPOUNDS; MAGNETO-OPTICAL EFFECTS; STRONTIUM OXIDES; SYMMETRY; TRANSITION TEMPERATURE; YTTRIUM OXIDES; ALKALINE EARTH METAL COMPOUNDS; ALLOYS; BARIUM COMPOUNDS; BISMUTH COMPOUNDS; CALCIUM COMPOUNDS; CHALCOGENIDES; COPPER COMPOUNDS; DIELECTRIC PROPERTIES; ELECTRICAL PROPERTIES; ELEMENTS; EUROPIUM COMPOUNDS; METALS; OXIDES; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES; QUASI PARTICLES; RARE EARTH COMPOUNDS; RARE EARTHS; STRONTIUM COMPOUNDS; SUPERCONDUCTORS; THERMODYNAMIC PROPERTIES; TRANSITION ELEMENT COMPOUNDS; YTTRIUM COMPOUNDS; 360207* - Ceramics, Cermets, & Refractories- Superconducting Properties- (1992-); 360204 - Ceramics, Cermets, & Refractories- Physical Properties; 665411 - Basic Superconductivity Studies- (1992-)

Citation Formats

Spielman, S R. Optical tests for broken time-reversal symmetry in the cuprate superconductors. United States: N. p., 1992. Web.
Spielman, S R. Optical tests for broken time-reversal symmetry in the cuprate superconductors. United States.
Spielman, S R. Wed . "Optical tests for broken time-reversal symmetry in the cuprate superconductors". United States.
@article{osti_6988327,
title = {Optical tests for broken time-reversal symmetry in the cuprate superconductors},
author = {Spielman, S R},
abstractNote = {Optical measurements have been made on YBa[sub 2]Cu[sub 3]O[sub 7] and Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8] to search for both spontaneous Faraday rotation (in transmission) and spontaneous Kerr rotation (reflection). The observation of these magneto-optical effects near Tc would be a clear indication that the superconductivity in the cuprate superconductors can be explained by a theory which predicts broken time-reversal (T) symmetry. In particular, the [open quotes]any on[close quotes] model of these materials predicts that T symmetry will be broken spontaneously as the material is cooled. The magneto-optical effects are expected to be quite small compared to the birefringence of the material. A method has been developed that uses a fiber-optic Sagnac interferometer to search for the magneto-optic signal. Incident upon the samples are two counter-propagating circularly polarized beams, whose electric fields have opposite time dependence. The interferometer detects Faraday or Kerr rotation by measuring the difference in phase between these beams after they have interacted with the sample. Because it is immune to birefringence in the sample, this method is superior to simply analyzing the polarization state of a single beam. Transmission experiments at 1060 nm wavelength were done with a modified fiber-optic gyroscope (a type of Sagnac interferometer). The nonreciprocal phase shift observed in the cuprates was less than the sensitivity (2 [mu]rad). A 670 nm interferometer was constructed to look for these effects in the visible portion of the spectrum, where other researchers have witnessed unusual polarization effects.Both reflection and transmission measurements at this wavelength indicate there are no magneto-optic effects to a sensitivity of 5 [mu]rad. This technique has been applied successfully to study ferromagnetic phase transitions in films of EuO and Gd.},
doi = {},
url = {https://www.osti.gov/biblio/6988327}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1992},
month = {1}
}

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