Ntshiab hlau lub feem ntau txhais cov cuab yeej sib nqus yog nws cov magnetic permeability siab. Qhov no txhais tau hais tias nws tso cai rau magnetic teb los ntawm nws nrog tsawg heev tsis kam. Thaum ib qho kev sib nqus sab nraud yog siv rau cov hlau ntshiab, cov hlau nplaum sib nqus hauv cov khoom siv nrawm nrawm nrog lub teb, tsim kom muaj lub zog sib nqus sab hauv. Qhov no muaj peev xwm ua kom sai thiab ua tau zoo dlhos nws magnetic domains nyob rau hauv teb rau sab nraud teb yog dab tsi ua rau cov hlau ntshiab xws li ib tug haib tivthaiv nyob rau hauv lub creation ntawm muaj zog hlau nplaum.
Lwm cov cuab yeej tseem ceeb ntawm cov hlau ntshiab yog nws qhov siab saturation magnetization. Saturation magnetization yog hais txog qhov siab tshaj plaws sib nqus flux ntom ntom uas cov khoom tuaj yeem ua tiav thaum nws yog magnetized tag nrho. Cov hlau ntshiab muaj qhov sib nqus magnetization siab heev, uas txhais tau hais tias nws tuaj yeem khaws ntau lub zog sib nqus. Cov cuab yeej no tseem ceeb tshwj xeeb hauv kev tsim cov hlau nplaum ruaj khov, qhov twg cov khoom siv hluav taws xob siab (kev ntsuas ntawm lub zog thiab ruaj khov ntawm cov hlau nplaum) xav tau.
Kev sib xyaw ua ke ntawm siab sib nqus permeability thiab saturation magnetization tso cai rau cov hlau ntshiab siv rau hauv kev tsim cov ntaub ntawv mos thiab tawv tawv. Cov ntaub ntawv sib nqus mos, raws li tau hais dhau los, tau yooj yim magnetized thiab demagnetized. Lawv yog siv nyob rau hauv daim ntawv thov uas yuav tsum tau muaj zog, tswj magnetic teb, xws li transformers thiab inductors. Cov hlau ntshiab lub siab permeability ua rau nws yog ib qho kev xaiv zoo heev rau cov ntawv thov no vim nws tso cai rau kev hloov pauv tau zoo thiab khaws cia ntawm lub zog sib nqus.
Ntawm qhov tod tes, cov khoom siv hlau nplaum nyuaj khaws lawv cov hlau nplaum tom qab tau hlau nplaum thiab siv cov hlau nplaum tas mus li. Thaum cov hlau ntshiab ib leeg tsis yog feem ntau siv los ua cov khoom sib nqus nyuaj vim nws txoj kev nyiam corrode thiab poob nws cov hlau nplaum thaum lub sij hawm, nws yog feem ntau alloyed nrog lwm yam xws li npib tsib xee, cobalt, thiab tsawg lub ntiaj teb hlau los tsim cov ntaub ntawv xws li alnico, neodymium- hlau-boron (NdFeB), thiab samarium-cobalt (SmCo). Cov hlau no tau txais txiaj ntsig zoo ntawm cov hlau ntshiab lub siab saturation magnetization thiab muab nws nrog corrosion kuj thiab ruaj khov ntawm lwm cov ntsiab lus, ua rau muaj zog, ruaj khov hlau nplaum ruaj khov.
Hauv kev tsim cov hlau nplaum, cov hlau ntshiab feem ntau tau ua tiav los ntawm ntau cov txheej txheem los txhim kho nws cov khoom sib nqus. Piv txwv li, nws yuav tsum tau annealed (rhuab thiab maj mam txias) los txo cov kev ntxhov siab sab hauv thiab txhim kho nws txoj kev sib nqus. Nws kuj tseem yuav ua haujlwm txias (deformed ntawm chav tsev kub) kom nws coercivity thiab stability. Cov kauj ruam ua haujlwm no, ua ke nrog kev ua tib zoo xaiv cov hlau thiab cov khoom siv, xyuas kom meej tias cov hlau nplaum kawg muaj cov khoom sib nqus uas xav tau thiab kev ua haujlwm zoo.
Hauv cov ntsiab lus, cov hlau ntshiab cov khoom sib nqus tshwj xeeb ntawm siab permeability thiab saturation magnetization ua rau nws yog ib qho tseem ceeb hauv kev tsim khoom ntawm ob qho tib si mos thiab tawv hlau nplaum. Txawm hais tias cov hlau ntshiab ib leeg tsis tuaj yeem siv los ua txhua hom hlau nplaum, nws lub luag haujlwm hauv kev sib nqus thiab kev ua haujlwm yog qhov tseem ceeb rau kev tsim kom muaj zog, ruaj khov, thiab ua haujlwm zoo sib nqus. Kev ceev faj ntawm cov hlau ntshiab cov khoom los ntawm kev sib xyaw ua ke thiab kev ua haujlwm tso cai rau kev tsim ntau yam khoom siv hlau nplaum uas haum rau cov kev siv tshwj xeeb, los ntawm cov compasses yooj yim mus rau complex industrial machinery.