PIRA 5G20.00 MAGNET DOMAINS AND MAGNETIZATION

DCS #DEMONSTRATIONREFERENCEABSTRACT
5G20.00Magnet Domains & Magnetization
5G20.10Barkhausen effectPIRA 500
5G20.10Barkhausen effect5G20.10Amplify the signal from a small coil as it is flipped in a magnetic field with copper, soft iron, and steel cores.
5G20.10Barkhausen effectEs-1Magnetic domains in the core of a small coil can be heard flipping as a magnet is moved by using and an audio amplifier.
5G20.10Barkhausen effect32-3.10Insert various cores into a coil connected to an audio amplifier and spin a magnet around it.
5G20.10Barkhausen effect32-3.11Stretch a iron-nickel alloy wire through a coil and bring a magnet close to demonstrate sudden simultaneous magnetization.
5G20.10Barkhausen effectE-94Soft iron and hard steel cores are placed in a small coil attached to an audio amplifier and the assembly is inserted into a magnetic field.
5G20.10Barkhausen effectE-10dA soft iron core inserted in a small coil connected to the input of an audio amplifier.
5G20.10Barkhausen effectDisc 19-19Pulses from moving a magnet near a coil wrapped around a soft iron core are amplified.
5G20.15spin-flop transition modelAJP 39(7),832A mechanical model of the spin-flip transition in antiferromagnets.
5G20.20ferro-optical garnetPIRA 500
5G20.20ferro-optical garnet5G20.20View a commercial ferro-optical garnet between crossed Polaroids with a color TV on a microscope as the field in the coil is changed.
5G20.21ferromagnetic garnet32-3.8Examine a crystal of M3Fe2(FeO4)3 in a polarizing microscope. Diagrams, Reference: AJP,27(3),201.
5G20.22Weiss domains32-3.9Examine a Gadolinium-Iron-Garnet crystal in a polarizing microscope as the magnetic field and temperature are changed. Picture, Reference: AJP,27(3),201.
5G20.23optical ferromagnetic domainsAJP 29(11),789Examine thin polished crystals under a low powered microscope in polarized light. Add a small coil to change the field.
5G20.27iron filing domains32-3.2A tube of compressed iron filings is magnetized and then the iron filings are agitated.
5G20.30magnetic domain modelPIRA 200An array of small compass needles shows domain structures.
5G20.30magnetic domainsEs-2An array of small compass needles shows domain structures.
5G20.30magnetic domain modelDisc 19-16A set of compass needles on pins.
5G20.31compass arrays5G20.31
5G20.31compass array32-3.7An array of compass needles made of spring steel strip stock shows domains under different magnetic field conditions.
5G20.31compass arrayE-91A set of magnetic needles on pivots orients randomly until a magnet is brought close. Barkhausen model - A compass array above an electromagnet will show that the needles align discontinuously as the field is increased.
5G20.36Heisenberg anitferromagnet modelAJP 54(12),1130A simple mechanical model demonstrates phase transitions in a Heisenberg antiferromagnet.
5G20.45induced magnetic polesPIRA 1000
5G20.45induced magnetic polesE-82A chain of nails is supported by a magnet, each becoming a magnet by induction.
5G20.46magnetic inductionE-88A soft iron bar held colinear with a permanent magnet will become magnetized by induction. Use a compass needle to show the far pole of the bar is the same as the near pole of the magnet.
5G20.50pound iron barPIRA 500
5G20.50pound iron bar5G20.50
5G20.50magnetization in the earth's fieldEr-8Hammer the end of a soft iron bar in the earth's magnetic field.
5G20.50pound iron bar32-3.4Pound a soft iron bar held in the earth's field, a permalloy bar does not need to be pounded.
5G20.50hammer an iron barE-80Hammer a soft iron bar held parallel to the field of the earth. A bar of permalloy is magnetized by simply holding it in the earth's field.
5G20.50magnetic induction in earth's fieldE-112Hammer the end of a soft iron rod held parallel to the earth's field. Hold a permalloy rod parallel while picking up pieces of permalloy ribbon, then turn perpendicular.
5G20.55permalloy barPIRA 500
5G20.55permalloy bar5G20.55
5G20.55permalloy barEr-9Iron filings stick to a permalloy bar held parallel to the earth's magnetic field but fall off when it is held perpendicular.
5G20.55permalloy in earth's fieldDisc 19-21A small strip of iron sticks to a permalloy rod when it is held in the direction of the Earth's field.
5G20.56permalloy rodE-6a.2Hold a permalloy rod near a compass needle.
5G20.60magnetization by currentPIRA 1000
5G20.60magnetization and demagnetizationE-127Place an iron core in a solenoid. Magnetize with direct current and demagnetize by reducing alternating current to zero.
5G20.60magnetization by currentE-83Place a piece of steel in a solenoid connected to a direct current source.
5G20.60magnetizing ironDisc 19-17Place an iron bar in a solenoid and pulse a large current.
5G20.61magnetization by contactPIRA 1000
5G20.61magnitizing iron by contactDisc 19-15Stroke a nail on a permanent magnet and it will pick up iron filings.
5G20.62demagnitization by hammeringPIRA 1000
5G20.62magnetization and demagnetizationE-78Stroke a steel needle with a permanent magnet to magnetize and pass it through an AC solenoid to demagnetize.
5G20.62demagnitizing iron by hammeringDisc 19-18Magnetize an iron bar in a solenoid, then pound it to demagnetize.
5G20.70electromagnet - lift personPIRA 500
5G20.70electromagnetEs-5A simple electromagnet.
5G20.70electromagnet with 1.5 V batteryDisc 19-12A magnet powered by a 1.5 V battery lifts a large weight.
5G20.71electromagnetPIRA 1000
5G20.71electromagnet5G20.71
5G20.71electromagnetE-126An electromagnet with 25 turns of wire and one dry cell can lift over 200 lbs.
5G20.72large electromagnetPIRA 1000
5G20.72magnet holding with small batteryEs-11An electromagnet energized with a small battery holds several Kg.
5G20.72large electromagnetDisc 19-11This magnet is made with 3000 turns and carries 25 amps.
5G20.73magnetic circuitAJP 34(7),623An iron loop with a coil on one side, a flux meter on the other, and a removable section for substituting various materials.
5G20.73measuring magnetic flux32-3.16Measure magnetic flux with and without a iron path. Not a good description.
5G20.74large electromagnetAJP 29(2),86Apparatus Drawings Project No. 13: A simple low cost electromagnet with 4"x4" pole faces, field of 1 weber/m2 with a .5 cm gap.
5G20.75retentivityPIRA 1000
5G20.75retentivity5G20.75
5G20.75retentivityE-96Two soft iron cores form a split toroid with a few turns of wire around one half. When the coil is energized the iron is strongly magnetized. When the current is off, the two pieces are still difficult to separate but once apart no longer attract.
5G20.75retentivityE-95A soft iron bar will cling to a "U" shaped electromagnet when the current is turned off but no longer attract after it is pulled away.
5G20.76different cores32-3.26An electromagnet is made with replaceable yoke to show the effect of different materials on lifting strength.

ReferenceDescription
M-1Sutton
Ma-1Freier & Anderson
M-1dHilton
8-2.8Meiners
1A12.01University of Minnesota Handbook
AJP 52(1),85American Journal of Physics
TPT 15(5),300The Physics Teacher
Disc 01-01The Video Encyclopedia of Physics Demonstrations

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