Lub magnetic permeability ntawm lub substance

Cov kev sib raug zoo ntawm cov sib nqus teb (H) thiab sib nqus flux ceev (B) nyob rau hauv cov ntaub ntawv uas yog yus muaj los ntawm ib tug lub cev muaj nuj nqis hu ua magnetic permeability. tsis magnetic permeability ntawm qhov nruab nrab - tus piv ntawm B rau H. Raws li cov International System of Chav yog ntsuas nyob rau hauv chav hu ua 1 henry ib 'meter'.

Ib tug numeric tus nqi qhia los ntawm tus piv ntawm nws cov magnitude rau lub qhov ntau ntawm nws cov magnetic permeability ntawm lub tshuab nqus tsev thiab yog denoted los ntawm μ. Qhov no tus nqi yog hu ua tus txheeb ze sib nqus permeability (los yog permeability) ntawm qhov nruab nrab. Yuav ua li cas yog tus txheeb ze, nws twb tsis muaj units.

Yog li ntawd, tus kwv tij sib nqus permeability μ - tus nqi uas qhia yuav ua li cas muaj ntau zaus nyob rau hauv lub induction tshav pob ntawm qhov nruab nrab yog tsawg (los yog ntau tshaj) ntawm lub tshuab nqus tsev induction magnetic teb.

Thaum kis tau tus yeeb tshuaj, nws yuav magnetized los ntawm cov sab nraud magnetic teb. Yuav ua li cas no tshwm sim? Raws li cov kev xav ntawm Ampere, nyob rau hauv txhua txhua teeb meem ntawm lossi circulating me me hluav taws xob currents tshwm sim los ntawm lub zog ntawm electrons nyob rau hauv lawv cov orbits thiab muaj ntawm lawv tus kheej magnetic caij. Nyob rau hauv tej yam kev mob, qhov no yog disordered, thiab lub teb "quenched" (rho) txhua lwm yam. Thaum ib tse nrog koj lub cev nyob rau hauv ib tug sab nraud teb lub currents ordering, thiab lub cev yuav magnetized (m. E. Muaj nws teb).

tag nrho cov tshuaj lub permeability yog sib txawv. Raws li rau ntawm tus nqi ntawd, raug teeb meem kev faib mus rau hauv peb pawg loj.

Nyob rau hauv diamagnetic nqi ntawm magnetic permeability μ - ib tug me ntsis tsawg tshaj li ib. Piv txwv li, Bismuth μ = 0,9998. Los ntawm diamagnetic yog zinc, hmoov txhuas, quartz, pob zeb ntsev, tooj liab, iav, hydrogen, benzene, dej.

Lub magnetic permeability ntawm paramagnetic me ntsis loj units (rau μ = 1,000023 txhuas). Piv txwv ntawm paramagnetic - npib tsib xee, oxygen, tungsten, ebonite, platinum, nitrogen, huab cua.

Thaum kawg, peb pab pawg neeg yuav ib tug xov tooj ntawm tej yam tshuaj (mas co thiab alloys), uas nws magnetic permeability yog ho (los ntawm ob peb kev txiav txim ntawm qhov ntau) tshaj kev sib sau. Cov tshuaj - ferromagnets. Yeej no muaj xws li npib tsib xee, hlau, cobalt thiab lawv alloys. Rau steel μ = 8 ∙ 10 ^ 3 rau cov npib tsib xee-hlau alloy μ = 2.5 ∙ 10 ^ 5. Ferromagnetic muaj zog uas paub qhov txawv lawv los ntawm lwm yam. Firstly, lawv muaj ib tug residual magnetism. Secondly, lawv permeability yog ib tug muaj nuj nqi ntawm cov sab nraud teb induction. Peb, rau txhua yam uas lawv muaj ib tug tej yam pib kub, hu ua lub Curie point uas nws loses nws ferromagnetic zog thiab yuav paramagnetic. Rau npib tsib xee Curie point - 360 ° C, hlau - 770 ° C.

Cov khoom ntawm ferromagnets txiav txim tsis tau tsuas yog permeability tab sis kuj cov magnitude kuv, xa mus rau raws li lub magnetization ntawm lub substance. Qhov no yog ib tug complex nonlinear muaj nuj nqi ntawm magnetic induction, kev loj hlob yog piav magnetization kab hu ua magnetization nkhaus. Yog li, thaum nej tau mus txog ib tug taw tes, lub magnetization suab tsis tu tsis tseg rau kom (magnetic saturation tshwm sim). Backlog nqi ferromagnetic magnetization los ntawm cov loj hlob rau magnitude ntawm lwm magnetic teb induction yog hu ua hysteresis. Nyob rau hauv cov ntaub ntawv no, muaj ib tug nyob tos ntawm ib tug ferromagnet ntawm lub magnetic yam ntxwv tsis tsuas yog nyob rau nws lub xeev nyob rau hauv lub sij hawm, tab sis kuj nyob rau hauv nws cov yav dhau los magnetization. Graphical sawv cev ntawm no nkhaus nuj nqi no yog hu ua hysteresis voj.

Vim nws cov khoom, ferromagnetic khoom siv nyob rau hauv cov kos duab. Lawv yog siv nyob rau hauv rotors ntawm motors thiab generators, nyob rau hauv qhov siv thiab ua transformer cores thiab electromagnetic relays, nyob rau hauv qhov siv thiab ua cov khoom hluav taws xob computers. Lub magnetic thaj chaw ntawm ferromagnetic ntaub ntawv no yog siv nyob rau hauv daim kab xev recorders, xov tooj, daim kab xev, thiab lwm yam cia media.