Cia peb xav txog qhov tseem ceeb ntawm kev siv ferromagnets, nrog rau cov yam ntxwv ntawm lawv cov kev faib tawm. Cia peb pib nrog qhov tseeb tias ferromagnets hu ua cov khib nyiab uas muaj kev tswj tsis tau cov hlau nplaum ntawm qhov kub qis. Nws hloov nyob rau hauv tus ntawm deformation, magnetic teb, kub fluctuations.
Properties of ferromagnets
Kev siv ferromagnets hauv thev naus laus zis tau piav qhia los ntawm lawv lub cev. Lawv muaj qhov sib nqus permeability uas ntau zaus ntau dua li lub tshuab nqus tsev. Hauv qhov no, txhua yam khoom siv hluav taws xob uas siv cov hlau nplaum sib nqus los hloov ib hom zog rau lwm qhov muaj cov khoom tshwj xeeb uas ua los ntawm cov khoom siv ferromagnetic muaj peev xwm ua tau cov hlau nplaum sib nqus.
Txoj kev ntawm ferromagnets
Dab tsi yog qhov txawv ntawm ferromagnets? Cov khoom thiab kev siv ntawm cov tshuaj no tau piav qhia los ntawm peculiarities ntawm cov qauv sab hauv. Muaj kev sib raug zoo ntawm cov khoom sib nqus ntawm cov teeb meem thiab cov khoom siv hluav taws xob theem qis, uas yog cov hluav taws xob txav mus rau hauv lub atom.
Thaum txav mus rau hauv lub voj voog ncig, lawv tsim cov tam sim no theem pib thiab sib nqusdipoles uas muaj lub sijhawm sib nqus. Nws cov kev taw qhia yog txiav txim los ntawm gimlet txoj cai. Lub sijhawm sib nqus ntawm lub cev yog qhov geometric sum ntawm txhua qhov chaw. Ntxiv nrog rau kev sib hloov hauv lub voj voog ncig, cov khoom siv hluav taws xob kuj txav mus los ntawm lawv tus kheej axes, tsim lub sijhawm tig. Lawv ua haujlwm tseem ceeb hauv cov txheej txheem magnetization ntawm ferromagnets.
Kev siv cov ferromagnets yog txuam nrog kev tsim nyob rau hauv lawv ntawm spontaneous magnetized cheeb tsam nrog rau qhov sib npaug ntawm kev taw qhia ntawm lub sijhawm tig. Yog hais tias lub ferromagnet tsis nyob rau hauv ib qho chaw sab nraud, ces tus neeg sib nqus lub sij hawm muaj cov lus qhia sib txawv, lawv cov lej yog xoom thiab tsis muaj cov khoom sib nqus.
Cov yam ntxwv tshwj xeeb ntawm ferromagnets
Yog tias paramagnets txuam nrog cov khoom ntawm tus kheej molecules lossis atoms ntawm ib yam khoom, ces ferromagnetic zog tuaj yeem piav qhia los ntawm qhov tshwj xeeb ntawm cov qauv siv lead ua. Piv txwv li, nyob rau hauv lub xeev vapor, hlau atoms yog me ntsis diamagnetic, thaum nyob rau hauv lub xeev cov khoom no hlau yog ib tug ferromagnet. Raws li qhov tshwm sim ntawm kev tshawb fawb hauv chav kuaj, kev sib raug zoo ntawm qhov kub thiab txias thiab ferromagnetic zog tau tshwm sim.
Piv txwv li, Goisler alloy, zoo ib yam hauv cov khoom sib nqus rau hlau, tsis muaj cov hlau no. Thaum Curie point (tus nqi ntsuas kub) tau mus txog, cov khoom ferromagnetic ploj.
Ntawm lawv cov yam ntxwv tshwj xeeb, ib tus tuaj yeem tawm tsis tau tsuas yog tus nqi siab ntawm magnetic permeability, tab sis kuj muaj kev sib raug zoo ntawm lub zog thiabmagnetization.
Kev sib cuam tshuam ntawm lub sijhawm sib nqus ntawm ib tus neeg atoms ntawm ferromagnet pab txhawb rau kev tsim cov hlau nplaum sab hauv uas muaj zog sib nqus uas sib npaug rau ib leeg. Qhov chaw sab nraud muaj zog ua rau muaj kev hloov pauv hauv kev taw qhia, uas ua rau muaj kev nce hauv cov khoom sib nqus.
Nature of ferromagnets
Cov kws tshawb fawb tau tsim qhov kev hloov pauv ntawm ferromagnetism. Thaum faib cov khoom siv hluav taws xob hla cov txheej txheem hluav taws xob, Pauli txoj cai tsis suav nrog yog muab rau hauv tus account. Nws lub ntsiab yog tias tsuas yog qee tus lej ntawm lawv tuaj yeem nyob ntawm txhua txheej. Cov txiaj ntsig tshwm sim ntawm lub orbital thiab spin magnetic moments ntawm tag nrho cov electrons nyob rau ntawm lub plhaub tag nrho yog sib npaug rau xoom.
tshuaj lom neeg nrog cov khoom ferromagnetic (nickel, cob alt, hlau) yog cov khoom hloov pauv ntawm lub sijhawm. Nyob rau hauv lawv cov atoms, muaj ib tug ua txhaum ntawm lub algorithm rau sau shells nrog electrons. Ua ntej, lawv nkag mus rau sab sauv txheej (s-orbital), thiab tsuas yog tom qab nws puv tag, cov electrons nkag mus rau lub plhaub nyob hauv qab (d-orbital).
Kev siv loj ntawm ferromagnets, lub ntsiab ntawm cov hlau, tau piav qhia los ntawm kev hloov hauv cov qauv thaum raug rau sab nraud magnetic teb.
Cov khoom zoo sib xws tuaj yeem tsuas yog muaj los ntawm cov khoom hauv cov atoms uas muaj cov plhaub sab hauv uas tsis tiav. Tab sis txawm tias tus mob no tsis txaus los tham txog cov yam ntxwv ferromagnetic. Piv txwv li, chromium, manganese, platinum kuj muajLub plhaub tsis tiav hauv atoms, tab sis lawv yog paramagnetic. Qhov tshwm sim ntawm kev sib nqus hlau nplaum yog piav qhia los ntawm qhov tshwj xeeb quantum nkaus, uas yog qhov nyuaj los piav qhia siv classical physics.
Department
Muaj kev faib cov ntaub ntawv no ua ob hom: tawv thiab mos ferromagnets. Kev siv cov ntaub ntawv nyuaj yog txuam nrog kev tsim cov khoom sib nqus, cov ntaub nplaum rau khaws cov ntaub ntawv. Mos ferromagnets yog indispensable nyob rau hauv lub creation ntawm electromagnets, transformer cores. Qhov sib txawv ntawm ob hom yog piav qhia los ntawm qhov peculiarities ntawm cov qauv tshuaj ntawm cov tshuaj no.
Txoj kev siv
Cia peb ua tib zoo saib qee qhov piv txwv ntawm kev siv ferromagnets hauv ntau ceg ntawm cov cuab yeej siv niaj hnub no. Cov ntaub ntawv sib nqus mos yog siv hauv hluav taws xob engineering los tsim hluav taws xob motors, transformers, generators. Tsis tas li ntawd, nws tseem ceeb heev uas yuav tsum nco ntsoov siv cov ferromagnets ntawm hom no hauv xov tooj cua sib txuas lus thiab cov cuab yeej siv qis tam sim no.
Cov hom nruj yog xav tau los tsim cov hlau nplaum ruaj khov. Yog tias qhov chaw sab nraud raug muab tua, ferromagnets khaws lawv cov khoom, txij li cov kev taw qhia ntawm cov tam sim no tsis ploj.
Nws yog cov cuab yeej no uas piav qhia txog kev siv ferromagnets. Hauv luv luv, peb tuaj yeem hais tias cov khoom siv no yog lub hauv paus ntawm cov cuab yeej siv niaj hnub no.
Cov hlau nplaum tas mus li yog xav tau thaum tsim cov cuab yeej ntsuas hluav taws xob, xov tooj, lub suab nrov, lub tshuab sib nqus, lub suab kaw.
Xav txog kev siv cov ferromagnets, nws yog ib qho tsim nyog yuav tau xyuam xim tshwj xeeb rau ferrites. Lawv tau dav siv nyob rau hauv high-frequency xov tooj cua engineering, txij li thaum lawv muab cov khoom ntawm semiconductors thiab ferromagnets. Nws yog los ntawm ferrites uas sib nqus tapes thiab films, cores ntawm inductors, thiab disks yog tam sim no. Lawv yog hlau oxides pom nyob rau hauv cov xwm.
Npaj qhov tseeb
Kev txaus siab yog kev siv cov ferromagnets hauv cov tshuab hluav taws xob, nrog rau kev siv tshuab ntawm kev kaw cia hauv lub hard drive. Kev tshawb fawb niaj hnub no qhia tau hais tias ntawm qee qhov kub, qee qhov ferromagnets tuaj yeem tau txais cov yam ntxwv paramagnetic. Tias yog vim li cas cov tshuaj no suav hais tias tsis to taub thiab yog qhov txaus siab rau cov kws kho mob.
Cov tub ntxhais hlau tuaj yeem ua kom cov hlau nplaum ntau zaus yam tsis hloov lub zog tam sim no.
Kev siv cov ferromagnets tuaj yeem txuag hluav taws xob ntau. Tias yog vim li cas cov ntaub ntawv nrog ferromagnetic zog yog siv rau cov cores ntawm generators, transformers, hluav taws xob motors.
Magnetic hysteresis
Qhov no yog qhov tshwm sim ntawm kev vam khom ntawm lub zog sib nqus thiab cov magnetization vector ntawm sab nraud. Cov cuab yeej no manifests nws tus kheej nyob rau hauv ferromagnets, raws li zoo raws li nyob rau hauv alloys ua los ntawm hlau, npib tsib xee, cob alt. Ib qho tshwm sim zoo sib xws tau pom tsis yog nyob rau hauv rooj plaub ntawm kev hloov pauv ntawm kev coj ua thiab qhov loj ntawm thaj teb, tab sis kuj tseem nyob rau hauv rooj plaub ntawm nws txoj kev sib hloov.
Kev nkag mus tau
Sib nqus permeability yog lub cev muaj nuj nqis uas qhia qhov piv ntawm induction nyob rau hauv ib qho nruab nrab rau qhov ntawd hauv lub tshuab nqus tsev. Yog hais tias ib yam khoom tsim nws tus kheej magnetic teb, nws raug xam tias yog magnetized. Raws li Ampère qhov kev xav, tus nqi ntawm cov khoom nyob ntawm lub orbital motion ntawm "dawb" electrons nyob rau hauv lub atom.
Lub voj hysteresis yog qhov nkhaus ntawm qhov kev vam khom ntawm qhov kev hloov pauv ntawm qhov loj ntawm cov hlau nplaum ntawm cov ferromagnet nyob rau hauv ib qho chaw sab nraud ntawm qhov kev hloov ntawm qhov loj ntawm induction. Yuav kom demagnetize tag nrho lub cev siv, koj yuav tsum tau hloov cov kev taw qhia ntawm sab nraud magnetic teb.
Ntawm ib qho nqi ntawm magnetic induction, uas yog hu ua lub zog quab yuam, lub magnetization ntawm tus qauv yuav xoom.
Nws yog cov duab ntawm lub voj voog hysteresis thiab qhov loj ntawm lub zog quab yuam uas txiav txim siab lub peev xwm ntawm cov khoom siv los tswj cov hlau nplaum ib nrab, piav qhia txog kev siv ferromagnets. Luv luv, cov cheeb tsam ntawm daim ntawv thov ntawm cov tawv ferromagnets nrog lub voj dav hysteresis tau piav qhia saum toj no. Tungsten, carbon, aluminium, chromium steels muaj lub zog loj, yog li ntawd, cov hlau nplaum ruaj khov ntawm ntau cov duab yog tsim los ntawm lawv lub hauv paus: sawb, horseshoe.
Ntawm cov ntaub ntawv mos nrog lub zog me me, peb nco ntsoov cov hlau ore, nrog rau cov hlau-nickel alloys.
Cov txheej txheem ntawm magnetization thim rov qab ntawm ferromagnets yog txuam nrog kev hloov hauv cheeb tsam ntawm kev sib nqus magnetization. Rau qhov no, kev ua haujlwm ua los ntawm sab nraud yog siv. Ntaulub tshav kub generated nyob rau hauv cov ntaub ntawv no yog proportional rau thaj tsam ntawm lub hysteresis voj.
Zoo kawg
Tam sim no, hauv txhua ceg ntawm kev siv tshuab, cov khoom siv ferromagnetic yog nquag siv. Ntxiv nrog rau kev txuag nyiaj tseem ceeb hauv kev siv hluav taws xob, kev siv cov khoom siv no tuaj yeem ua kom yooj yim cov txheej txheem thev naus laus zis.
Piv txwv li, riam phom nrog cov hlau nplaum ruaj khov, koj tuaj yeem ua kom yooj yim ntawm kev tsim tsheb. Cov tshuab hluav taws xob muaj zog, tam sim no siv nyob rau hauv tsev thiab txawv teb chaws tsheb cov nroj tsuag, ua kom nws muaj peev xwm ua kom tiav cov txheej txheem thev naus laus zis ntau tshaj plaws, nrog rau kev ua kom cov txheej txheem ntawm kev sib sau cov tsheb tshiab.
Hauv xov tooj cua engineering, ferromagnets ua kom tau txais cov khoom siv zoo tshaj plaws thiab raug.
Cov kws tshawb fawb tau ua tiav hauv kev tsim ib txoj hauv kev los tsim cov hlau nplaum nanoparticles uas tsim nyog rau kev siv tshuaj thiab khoom siv hluav taws xob.
Raws li qhov tshwm sim ntawm ntau qhov kev tshawb fawb tau ua nyob rau hauv qhov chaw tshawb fawb zoo tshaj plaws, nws muaj peev xwm tsim cov khoom sib nqus ntawm cob alt thiab hlau nanoparticles coated nrog nyias txheej ntawm kub. Lawv lub peev xwm hloov cov tshuaj tiv thaiv kab mob los yog radionuclide atoms mus rau sab xis ntawm tib neeg lub cev thiab ua kom qhov sib txawv ntawm cov duab sib nqus resonance twb tau lees paub lawm.
Ntxiv rau qhov no, cov khoom siv no tuaj yeem siv los hloov kho cov cuab yeej sib nqus nco, uas yuav yog kauj ruam tshiab hauv kev tsim kho tshiab.kho mob technology.
Ib pab pawg ntawm cov kws tshawb fawb Lavxias tau tswj hwm los tsim thiab sim ib txoj hauv kev los txo cov tshuaj chlorides kom tau txais kev sib xyaw cob alt-hlau nanoparticles haum rau tsim cov khoom siv nrog cov yam ntxwv zoo sib nqus. Txhua qhov kev tshawb fawb ua los ntawm cov kws tshawb fawb yog tsom rau kev txhim kho cov khoom ferromagnetic ntawm cov khoom, nce lawv feem pua ntawm kev siv ntau lawm.
