Cov hlau nplaum ntawm cov teeb meem los ntawm lub sij hawm sib nqus ntawm electrons hauv atoms
Cov khoom yog tsim los ntawm atoms, uas yog tsim los ntawm nuclei thiab electrons. Nyob rau hauv atoms, electrons muaj orbital magnetic moments vim hais tias lawv tsiv mus nyob ib ncig ntawm lub nucleus; electrons muaj spin magnetic moments vim spin. Lub sijhawm sib nqus ntawm atoms feem ntau yog los ntawm lub sijhawm electron magnetic, uas yog lub hauv paus ntawm cov hlau nplaum ntawm tag nrho cov ntaub ntawv.
Lub sij hawm sib nqus yog ib qho kev taw qhia vector. Cov kiv cua ntawm electrons hauv atoms tau muab faib ua ob hom: nce thiab nqis. Nyob rau hauv feem ntau cov ntaub ntawv, muaj ntau npaum li electrons nrog upward spin li muaj downward spin. Lub sijhawm sib nqus lawv tsim tawm ib leeg tawm, thiab tag nrho cov atom tsis muaj cov hlau nplaum sab nraud. Tsuas yog qee qhov teeb meem atoms muaj cov lej sib txawv ntawm cov hluav taws xob sib txawv hauv cov lus qhia sib txawv. Nyob rau hauv no txoj kev, tom qab lub sij hawm sib nqus ntawm electrons nrog opposite spin tshem tawm ib leeg tawm, lub spin magnetic moments ntawm seem electrons tsis tau muab tso tseg, thiab tag nrho cov atom muaj tag nrho cov magnetic moments. Lub sijhawm sib nqus ntawm ib lub atom nyob ntawm cov qauv atomic, thiab atoms ntawm tag nrho cov ntsiab lus nyob rau hauv lub sij hawm muaj lawv tus kheej lub sij hawm sib nqus.
Vim lub sijhawm sib nqus sib nqus ntawm cov atom sib txawv, kev sib cuam tshuam ntawm atomic magnetic moments ntawm macroscopic tshuaj ua rau muaj kev sib txawv ntawm atomic magnetic moments ntawm chav tsev kub. Raws li qhov sib txawv ntawm qhov sib nqus sib nqus thiab sib nqus ntawm cov tshuaj macroscopic nyob rau hauv sab nraud magnetic teb, lawv muab faib ua paramagnetic tshuaj, diamagnetic tshuaj, ferromagnetic tshuaj, ferrimagnetic tshuaj, thiab antiferromagnetic tshuaj.
Sib nqus lub sij hawm thiab sib nqus flux: tuaj yeem hloov pauv los ntawm coil tas li
Sib nqus lub sij hawm thiab magnetic teb yog ob qho tib si tsis tseem ceeb uas piav txog lub zog sib nqus ntawm cov khoom siv hlau nplaum ruaj khov. Muaj qee qhov kev sib raug zoo ntawm lawv, tab sis lawv yog lub cev muaj nuj nqis nrog lub ntsiab lus sib txawv.
Txoj kev sim siv feem ntau rau lub sijhawm sib nqus yog ua raws li International Electrotechnical Commission tus qauv IEC60404-14 (rub lossis tig txoj kev los ntsuas lub sijhawm sib nqus dipole ntawm cov ntaub ntawv ferromagnetic). Kev ntsuas ntawm lub sijhawm sib nqus yog xam los ntawm kev ntsuas qhov qhib Circuit Court magnetic flux. Los ntawm kev ntsuas qhov qhib-circuit qauv nyob rau hauv ib-dimensional Helmholtz coil nrog nruj nreem calibrated kauj tas li ntawm k, qhov sib nqus flux nqi Ø tuaj yeem tau, thiab lub sijhawm sib nqus M ntawm cov khoom tuaj yeem xam los ntawm tus nqi sib nqus flux. Muab xam raws li nram no:
M = k * ФM
Sawv cev lub sij hawm sib nqus ntawm cov hlau nplaum, chav tsev yog Wb·cm-1k nruab nrab ntawm lub coil tas li, chav tsev: cm-1 (lub tsev hloov ntawm lub coil tsis tu ncua yuav ua rau kev hloov pauv ntawm lub sijhawm sib nqus chav tsev )
Ф sawv cev tus nqi sib nqus flux, chav tsev: Wb
Rau tib cov hlau nplaum, qhov sib nqus flux qhov tseem ceeb ntsuas nyob rau hauv qhov sib txawv coil tas li yog qhov sib txawv, tab sis lub sijhawm sib nqus sib nqus yog tib yam. Yog li ntawd, qhov sib nqus lub sij hawm sib txuas lus ntawm cov neeg yuav khoom thiab cov muag khoom yuav muaj tseeb dua thiab ua haujlwm tau zoo.