Magnetic Bubble

a portion of computer memory which consists of a small region in a material such as garnet (a silicate mineral), which is magnetized in one direction. Slices of this material placed on a SUBSTRATE (base material) produce a magnetic chip that under a magnetic field produces magnetic bubbles. Information can be stored on the chip, which may contain up to one million bubbles in 20 square millimetres, in BINARY form, through the presence or absence of a bubble in a specific location.

Taken from Dictionary of Science

«««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««

The magnetic bubble apparatus consists of a thin (8-12μm) single crystal film of Ferromagnetic Garnet (FMG) sandwiched between a pair of crossed Polaroids. The FMG crystals are magnetically anisotropic, that is, they have a strong tendency to orient themselves in fixed directions under the influence of an external magnetic field. The preferred or "easy" axis of orientation is perpendicular to (in or out of) the crystal surface. With no external magnetic field, the domains in the crystal orient up or down in roughly equal amounts. Polarized light passing through the crystal will have its plane of polarization rotated by due to interaction with the magnetic field of the domains (an effect called Faraday rotation). For the 'up' domains, the light will be crossed with respect to the exiting Polaroid therefore appearing dark, and for 'down' domains uncrossed (or vice versa) so appearing bright. The domains appear as serpentine patterns of alternating bright and dark (figure 1a.). Application of an external magnetic field (provided by a built-in electromagnet) flips the domains to one preferred orientation. As the field is increased, the serpentine patterns gradually disappear until you are left with one or two strings and isolated "bubbles".

Taken from fas.harvard.edu

Kaolinite

aluminium silicate with water in its structure which occurs as an alteration product in IGNEOUS ROCKS, GNEISSES and a weathering and hydrothermal reaction product in sedimentary products. It is used in ceramics and as a coating and filler in the paper industry.

Taken from Dictionary of Science

_____________________________________________________________

Kaolinite is a clay mineral with the chemical composition Al₂Si₂O₅(OH)₄. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra. Rocks that are rich in kaolinite are known as china clay, white clay, or kaolin.

The name is derived from Gaoling or Kao-Ling (高嶺; "High Hill") in Jingdezhen, Jiangxi province, China. Kaolinite was first described as a mineral species in 1867 for an occurrence in the Jari River basin of Brazil.

Kaolinite has a low shrink-swell capacity and a low cation exchange capacity (1-15 meq/100g.) It is a soft, earthy, usually white mineral (dioctahedral phyllosilicate clay), produced by the chemical weathering of aluminium silicate minerals like feldspar. In many parts of the world, it is colored pink-orange-red by iron oxide, giving it a distinct rust hue. Lighter concentrations yield white, yellow or light orange colours. Alternating layers are sometimes found, as at Providence Canyon State Park in Georgia, USA.

Taken from Wikipedia

Ultrabasic Rock

an IGNEOUS ROCK that contains many silicate minerals of iron and magnesium such as AMPHIBOLES and PYROXENES, and with SILICA occurring as quartz.

Taken from Dictionary of Science

______________________________________

An igneous rock with a very low silica content and rich in minerals such as hypersthene, augite and olivine. These rocks are also known as ultramafic rocks.

Taken from Geology.com