Muaj hysteresis sib nqus, ferroelectric, dynamic, elastic. Nws kuj muaj nyob rau hauv biology, av science, economics. Ntxiv mus, lub ntsiab lus ntawm qhov kev txhais no yuav luag tib yam. Tab sis tsab xov xwm yuav tsom rau cov hlau nplaum, koj yuav kawm ntxiv txog qhov tshwm sim no, nws nyob ntawm dab tsi thiab thaum nws tshwm sim nws tus kheej. Qhov tshwm sim no tau kawm hauv cov tsev kawm ntawv qib siab uas muaj kev tsom xam, nws tsis suav nrog hauv tsev kawm cov ntaub ntawv kawm, yog li tsis yog txhua tus paub txog nws.
Hysteresis magnetic
Qhov no yog qhov tsis tuaj yeem rov qab thiab tsis pom tseeb ntawm kev sib nqus ntawm cov khoom siv (thiab cov no yog, raws li txoj cai, cov hlau nplaum xaj ferromagnets) ntawm qhov chaw sib nqus sab nraud. Nyob rau hauv cov ntaub ntawv no, lub teb yog tas li hloov - txo los yog nce. Qhov laj thawj dav dav rau lub neej ntawm hysteresis yog qhov muaj lub xeev tsis ruaj khov thiab lub xeev ruaj khov ntawm qhov tsawg kawg nkaus ntawm cov peev txheej thermodynamic, thiab tseem muaj kev hloov pauv tsis tau ntawm lawv. Hysteresis kuj yog ib qho kev tshwm sim ntawm thawj-txiav magnetic orientational theem hloov. Nrog lawv, kev hloov pauv ntawm ib theem mus rau lwm qhov tshwm sim vim yog metastable xeev. Cov yam ntxwv yog ib daim duab, uas yog hu ua "hysteresis voj". Qee lub sij hawm nws tseem hu ua "magnetization nkhaus".
Hysteresis voj
Ntawm daim duab ntawm M piv rau H koj tuaj yeem pom:
- Los ntawm lub xeev xoom, uas M=0 thiab H=0, nrog kev nce hauv H, M kuj loj tuaj.
- Thaum daim teb nce, qhov magnetization yuav luag tas li thiab sib npaug rau tus nqi saturation.
- Thaum H txo qis, qhov kev hloov pauv tshwm sim, tab sis thaum H=0, qhov sib nqus M yuav tsis sib npaug rau xoom. Qhov kev hloov no tuaj yeem pom los ntawm qhov demagnetization nkhaus. Thiab thaum H=0, M siv tus nqi sib npaug rau qhov seem magnetization.
- As H nce nyob rau hauv ntau –Hm… +Hm, lub magnetization hloov raws tus thib peb nkhaus.
- Txhua peb txoj kab nkhaus piav qhia cov txheej txheem txuas nrog thiab tsim ib hom voj voog. Nws yog nws uas piav txog qhov tshwm sim ntawm hysteresis - cov txheej txheem ntawm magnetization thiab demagnetization.
Magnetization zog
Lub voj yog suav tias yog asymmetric nyob rau hauv rooj plaub thaum lub maxima ntawm H1 teb, uas yog siv nyob rau hauv lub rov qab thiab rau pem hauv ntej cov lus qhia, tsis zoo ib yam. Lub voj tau piav qhia saum toj no, uas yog tus yam ntxwv ntawm cov txheej txheem sib nqus qeeb qeeb. Nrog rau lawv, quasi-equilibrium kev sib raug zoo ntawm tus nqi ntawm H thiab M yog khaws cia.tias thaum lub sij hawm magnetization los yog demagnetization, M lags qab H. Thiab qhov no ua rau lub fact tias tag nrho cov zog uas tau txais los ntawm cov khoom ferromagnetic thaum lub sij hawm magnetization tsis tag kis thaum lub sij hawm demagnetization voj voog. Thiab qhov sib txawv no mus rau hauv cov cua sov ntawm ferromagnet. Thiab lub voj sib nqus hysteresis hloov mus ua asymmetric hauv qhov no.
Loop Shape
Cov duab ntawm lub voj yog nyob ntawm ntau yam tsis muaj - magnetization, teb lub zog, muaj qhov poob, thiab lwm yam. Cov tshuaj muaj pes tsawg leeg ntawm ferromagnet, nws cov qauv, qhov kub thiab txias, qhov xwm txheej thiab kev faib tawm ntawm qhov tsis xws luag Kev ua haujlwm (thermal, thermomagnetic, mechanical). Yog li ntawd, hysteresis ntawm ferromagnets tuaj yeem hloov pauv los ntawm kev xa cov ntaub ntawv mus rau kev siv tshuab. Qhov no hloov tag nrho cov yam ntxwv ntawm cov khoom.
Hysteresis poob
Thaum lub sijhawm muaj zog remagnetization ntawm ferromagnet los ntawm qhov chaw sib nqus sib nqus, kev poob raug pom. Ntxiv mus, lawv tsuas yog ib feem me me ntawm tag nrho cov hlau nplaum poob. Yog hais tias lub voj voog muaj qhov siab tib yam (qhov siab tshaj plaws ntawm cov hlau nplaum M), qhov dynamic hom voj yog dav dua li qhov zoo li qub. Qhov no yog vim qhov tseeb tias qhov kev poob tshiab tau ntxiv rau txhua qhov kev poob. Cov no yog dynamic poob, lawv feem ntau yog txuam nrog eddy tam sim no, sib nqus viscosity. Nyob rau hauv tas li ntawd, qhov tseem ceeb hysteresis poob tau.
Ib-domain ferromagnets
BYog hais tias cov khoom muaj qhov sib txawv, cov txheej txheem ntawm kev sib hloov yuav tshwm sim. Qhov no tshwm sim vim tias kev tsim cov thawj tswj hwm tshiab tsis zoo los ntawm lub zog ntawm qhov pom. Tab sis cov txheej txheem ntawm particle rotation yog hindered los ntawm anisotropy (magnetic). Nws tuaj yeem muaj qhov sib txawv ntawm cov hauv paus chiv keeb - tsim nyob rau hauv cov siv lead ua nws tus kheej, tshwm sim vim kev ntxhov siab elastic, thiab lwm yam). Tab sis nws yog precisely nrog kev pab los ntawm no anisotropy uas lub magnetization yog tuav los ntawm sab hauv teb. Nws tseem hu ua qhov zoo sib nqus anisotropy teb. Thiab magnetic hysteresis tshwm sim vim lub fact tias cov magnetization hloov nyob rau hauv ob txoj kev - rau pem hauv ntej thiab rov qab. Thaum lub sij hawm remagnetization ntawm ib leeg-domain ferromagnets, ntau jumps tshwm sim. Lub magnetization vector M tig mus rau qhov chaw H. Ntxiv mus, qhov tig tuaj yeem ua ib yam lossis tsis sib xws.
Multi-domain ferromagnets
Nyob rau hauv lawv, qhov nkhaus magnetization yog tsim nyob rau hauv ib txoj kev zoo sib xws, tab sis cov txheej txheem txawv. Thaum lub sij hawm magnetization reversal, lub domain ciam teb hloov. Yog li ntawd, ib qho ntawm qhov ua rau hysteresis tuaj yeem yog qhov ncua sij hawm ntawm kev hloov pauv ntawm ciam teb, nrog rau kev dhia irreversible. Qee lub sij hawm (yog tias ferromagnets muaj qhov loj me), qhov sib nqus hysteresis yog txiav txim siab los ntawm kev ncua ntawm kev loj hlob thiab tsim ntawm magnetization reversal nuclei. Nws yog los ntawm cov nuclei no uas cov qauv ntawm cov tshuaj ferromagnetic tsim.
Hysteresis theory
Nws yuav tsum raug coj mus rau hauv tus account tias qhov tshwm sim ntawm magnetic hysteresis kuj tshwm sim thaum lub teb H tig, thiab tsis yog thaum nws hloov pauv hauv kev kos npe thiabqhov loj. Qhov no yog hu ua hysteresis ntawm kev sib nqus sib nqus thiab sib raug rau kev hloov pauv ntawm cov kev taw qhia ntawm cov hlau nplaum M nrog kev hloov pauv ntawm qhov chaw H. Qhov tshwm sim ntawm hysteresis ntawm kev sib nqus sib nqus kuj tau pom thaum tus qauv tig txheeb ze. mus rau qhov chaw ruaj H.
Qhov nkhaus magnetization kuj qhia cov qauv sib nqus ntawm cov npe. Cov qauv hloov thaum lub sij hawm dhau los ntawm magnetization thiab magnetization reversal txheej txheem. Cov kev hloov pauv nyob ntawm seb thaj tsam thaj tsam hloov mus deb npaum li cas thiab ntawm qhov cuam tshuam ntawm qhov chaw sib nqus sab nraud. Tag nrho txhua yam uas tuaj yeem ncua tag nrho cov txheej txheem tau piav qhia saum toj no tso ferromagnets rau hauv lub xeev tsis ruaj khov thiab ua rau sib nqus hysteresis tshwm sim.
Nws yuav tsum tau coj mus rau hauv tus account tias hysteresis nyob ntawm ntau yam tsis muaj. Lub magnetization hloov nyob rau hauv lub cuam tshuam ntawm lwm yam - kub, elastic kev nyuaj siab, yog li ntawd, hysteresis tshwm sim. Nyob rau hauv cov ntaub ntawv no, ib tug hysteresis tshwm tsis tau tsuas yog nyob rau hauv lub magnetization, tab sis kuj nyob rau hauv tag nrho cov khoom uas nws nyob ntawm. Raws li tuaj yeem pom los ntawm no, qhov tshwm sim ntawm hysteresis tuaj yeem pom tsis tau tsuas yog thaum lub sijhawm sib nqus ntawm cov khoom siv, tab sis kuj thaum lwm yam txheej txheem ntawm lub cev cuam tshuam ncaj qha lossis tsis ncaj qha nrog nws.
