ASTM A883/A883M-01

Standard Test Method for Ferrimagnetic Resonance Linewidth and Gyromagnetic Ratio of Nonmetallic Magnetic Materials (Withdrawn 2006)

SCOPE
1.1 This test method covers the measurement of the ferrimagnetic resonance linewidth and gyromagnetic ratio of isotropic microwave ferrites. This test is restricted to spherical specimens possessing resonance linewidths greater than 10 Oe [796 A/m].
1.2 The values and equations stated in customary (cgs-emu and inch-pound) or SI units are to be regarded separately as standard. Within this standard, SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
WITHDRAWN RATIONALE
This test method covers the measurement of the ferrimagnetic resonance linewidth and gyromagnetic ratio of isotropic microwave ferrites. This test is restricted to spherical specimens possessing resonance linewidths greater than 10 Oe [796 A/m].
Formerly under the jurisdiction of Committee A06 on Magnetic Properties, this test method was withdrawn in May 2006 due to lack of interest in its continued use.

General Information

• Status: Withdrawn
• Publication Date: 09-Oct-2001
• Withdrawal Date: 17-May-2006
• ICS: 29.030 - Magnetic materials
• Technical Committee: A06 - Magnetic Properties
• Drafting Committee: A06.01 - Test Methods

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:A883/A883M–01
Standard Test Method for
Ferrimagnetic Resonance Linewidth and Gyromagnetic
Ratio of Nonmetallic Magnetic Materials
ThisstandardisissuedunderthefixeddesignationA883/A883M;thenumberimmediatelyfollowingthedesignationindicatestheyear
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope specimen, the dependence on specimen magnetization drops
out and the effective gyromagnetic ratio can be computed from
1.1 This test method covers the measurement of the ferri-
the relationship:
magnetic resonance linewidth and gyromagnetic ratio of iso-
tropic microwave ferrites. This test is restricted to spherical v5gH (1)
r
specimens possessing resonance linewidths greater than 10 Oe
where:
[796 A/m].
v =2pf;
1.2 The values and equations stated in customary (cgs-emu
f = microwave frequency, MHz; and
and inch-pound) or SI units are to be regarded separately as
H = resonance magnetic field strength, Oe [A/m].
r
standard. Within this standard, SI units are shown in brackets.
2.3 The second quantity characteristic of the absorption is
Thevaluesstatedineachsystemmaynotbeexactequivalents;
the ferrimagnetic resonance linewidth, DH, which for the
therefore,eachsystemshallbeusedindependentlyoftheother.
method described shall be defined as the separation of the two
Combining values from the two systems may result in noncon-
magnetic field values at which the power absorbed by the
formance with this standard.
ferrite material is one half the maximum absorption. The
1.3 This standard does not purport to address all of the
performance obtainable in specific devices such as isolators,
safety concerns, if any, associated with its use. It is the
rotators, and so forth, is related to the linewidth and gyromag-
responsibility of the user of this standard to establish appro-
netic ratio.
priate safety and health practices and determine the applica-
2.4 This test method of measuring the ferrimagnetic reso-
bility of regulatory limitations prior to use.
nancelinewidthandthegyromagneticratioofaferritematerial
uses a cavity perturbation technique, which requires that the
2. Summary of Test Methods
specimen be small compared to one quarter of the wavelength
2.1 Ferrite materials, in general, exhibit at microwave fre-
of the microwave radiation in the sample. Estimation of this
quencies a power loss or absorption which is a function of an
wavelength requires knowledge of the relative dielectric con-
appliedDCmagneticfield.Inmanyferrites,thisdependenceis
stant, k, and permeability, k , of the specimen material under
m
of a simple form, having a single maximum at some value of
the conditions of measurement. The relative permeability
themagneticfield,whichdependsonthemicrowavefrequency
depends on both the frequency and the magnetic field, but can
and on the specimen shape. For ferrite materials showing this
be taken as−2 for the resonance condition in a sphere. The
behavior,itisusefultocharacterizetheabsorptionbymeansof
wavelength in centimetres, l, in the specimen is then approxi-
an effective gyromagnetic ratio and a resonance linewidth.
mated by the equation:
Note that ferrite materials exist for which the absorption has a
morecomplexbehaviorasafunctionofDCmagneticfield;this l53 310 /=k
(2)
method is not intended to apply to such materials.
2.2 The value of the field for maximum absorption or
2.5 The absorption in the specimen is measured by deter-
resonance may be computed in terms of the magnetization of
mining the changes of power incident on the cavity required to
the sample, its geometry, the effective gyromagnetic ratio, g,
keep the output power from the cavity at a fixed reference
and the test frequency. For the case of a small spherical
level. It is necessary that the microwave frequency be adjusted
to cavity resonance for all measurements. The variations in
input power may be characterized by the variations of the
This test method is under the jurisdiction of ASTM Committee A06 on
attenuationinsertedbetweenamonitoredsourceandthecavity
MagneticPropertiesandisthedirectresponsibilityofSubcommitteeA06.01onTest
to maintain the reference output level. If a is this attenuator
Methods. 0
Current edition approved Oct. 10, 2001. Published December 2001. Originally reading in decibels with no sample present, and a is this
r
published as C524–63T. ASTM Test Method F130–86 was redesignated as
reading for maximum specimen absorption, then the reading
A883–86e in 1989. Last previous edition A 883–96.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A883/A883M
corresponding to a specimen absorption of half the resonance 9000and10000MHz,withaloadedQ(Q )greaterthan2000.
value is given by the equation: The specimen is positioned away from the cavity walls at a
point of minimum microwave electric field and maximum
~a 2a /20!
0 r
a 5a 120 log2 220 log 10 11
~ !
1/2 0
microwave magnetic field. In Fig. 2 a suitable cavity is shown
(3)
and the proper specimen position is indicated.The specimen is
3. Significance and Use
mounted on a fused silica or other dielectric rod. The hole for
inserting the specimen into the cavity is located in the narrow
3.1 This test method can be used to evaluate materials such
cavity wall and is no larger than 0.075 in. [1.90 mm] in
asgarnetsandsoforthforintrinsiclossfactorsthatcanbeused
in the design of microwave devices such as absorbers, circu- diameter for the X-band cavity. The input and output lines to
t
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