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Exchange-Coupled Amorphous Uranium Antimonide Magneto-Optic Materials

IP.com Disclosure Number: IPCOM000119363D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

Gambino, RJ: AUTHOR [+5]

Abstract

Disclosed is a way to increase the Curie temperature of amorphous USb alloys by exchange coupling. An exchange-coupled sandwich was prepared consisting of an amorphous USb layer between two layers of polycrystalline cobalt. The layers were deposited by magnetron sputtering without breaking vacuum between layers to ensure intimate contact between the layers. The cobalt is ferromagnetic at room temperature (Tc = 1300oK) whereas the amorphous USb alloy is paramagnetic at room temperature (Tc = 135oK). The approximate composition of the alloy used is 45U55Sb. The Faraday rotation of one of these sandwich structures is shown in the figure. The film consists of 200 Ao Co/200 Ao USb/200 Ao Co. The Faraday rotation of the sandwich decreases monotonically as a function of temperature from about 1.2 Mdeg/cm at 10oK to about 0.

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Exchange-Coupled Amorphous Uranium Antimonide Magneto-Optic Materials

      Disclosed is a way to increase the Curie temperature of
amorphous USb alloys by exchange coupling.  An exchange-coupled
sandwich was prepared consisting of an amorphous USb layer between
two layers of polycrystalline cobalt.  The layers were deposited by
magnetron sputtering without breaking vacuum between layers to ensure
intimate contact between the layers.  The cobalt is ferromagnetic at
room temperature (Tc = 1300oK) whereas the amorphous USb alloy is
paramagnetic at room temperature (Tc = 135oK).  The approximate
composition of the alloy used is 45U55Sb.  The Faraday rotation of
one of these sandwich structures is shown in the figure.  The film
consists of 200 Ao Co/200 Ao USb/200 Ao

Co.

  The Faraday rotation of
the sandwich decreases monotonically as a function of temperature
from about 1.2 Mdeg/cm at 10oK to about 0.5 Mdeg/cm at 300oK. The
rotation of a single layer of USb in the same magnetic field is also
shown.  The Co is essentially fully saturated in the applied field of
40 kG at room temperature and below because of its high Curie
temperature.  If it is assumed that at 300oK only the Co is magnetic,
the rotation of the USb in the sandwich can be extracted by
subtracting off the room temperature Co rotation from the low
temperature data. The difference between the USb single layer and the
USb in the sandwich is the enhancement which is shown by the
triangles connected by the solid line (the difference is shown
multiplied by 10 in the figure).  The enhancement is about
0.12Mdeg/cm at 140oK and 0.03Mdeg/cm at 160oK.  The...