Accession Number:

AD0006192

Title:

THE LOW-TEMPERATURE TRANSITION IN MAGNETITE

Descriptive Note:

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR INSULATION RESEARCH

Personal Author(s):

• Abrahams, S. C.
• Calhoun, B. A.

Report Date:

1953-02-01

Pagination or Media Count:

7.0

Abstract:

Magnetite was shown to transform from the cubic to the orthorhombic system at temperatures below 119 deg K. The thermal expansion coefficient of the c axis became negative below 119 deg K, and at about 95 deg K there was no appreciable difference in the spacing of 440 and 008. The dimensions of the magnetite unit cell were measured at 295 deg, 128 deg, and 78 deg K and the resulting volumes were 591.4, 589.1, and 589.6 A to the power of 3, respectively. From these data and the c-axis length at 108 deg K, the coefficients of thermal expansion above and below the transition were calculated.

Descriptors:

• *MAGNETITE
• THERMAL EXPANSION
• PHASE TRANSFORMATIONS
• COEFFICIENTS

Subject Categories:

• Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE