atichaalakata

is lekh mein sandarbh ya sootr naheen diye gaye hain.
krupaya vishvasaneeya sootron ke sandarbh jodkar is lekh mein sudhaar karein. bina sootron ki saamagri ko hataaya ja sakta hai. (September 2014)

kuchh padaarth atyant kam taap par poornat: shoonya pratirodhakata pradarshit karte hain. unke is gun ko atichaalakata (superconductivity) kehte hain. shoonya pratirodhakata ke alaava atichaalakata ki dasha mein padaarth ke bheetar chumbakeeya kshetr bhi shoonya ho jaata hai jise mesanar prabhaav (Meissner effect) ke naam se jaana jaata hai.

atichaalakon mein taap ke saath pratirodhakata ka parivartan

suvidit hai ki dhaatvik chaalakon ki pratirodhakata unka taap ghataane par ghatati jaati hai. kintu saamaanya chaalakon jaise taaainba aur chaaaindi aadi mein, ashuddhiyon aur doosare apoornataaon (defects) ke kaaran ek seema ke baad pratirodhakata mein kami naheen hoti. yahaaain tak ki taaainba (kaupar) param shoonya taap par bhi ashoonya pratirodhakata pradarshit karta hai. iske vipreet, atichaalak padaarth ka taap kraantik taap se neeche le jaane par, iski pratirodhakata teji se shoonya ho jaati hai. atichaalak taar se bane hue kisi band paripth ki vidyut dhaara kisi vidyut srot ke bina sada ke liye sthir rah sakti hai.

atichaalakata ek pramaatra-yaantrik drugvishya (quantum mechanical phenomenon.) hai. atichaalak padaarth chunbakeeya parilkshan ka bhi prabhaav pradarshit karte hain. in sabka taap-vaidyut-bal shoonya hota hai aur taamasan-gunaank baraabar hota hai. sankraman taap par inki vishisht ushma mein bhi akasmaat parivartan ho jaata hai.

yeh vishesh ullekhaneeya hai ki jin paramaanuon mein baahya ilektraunon ki sankhya 5 athva 7 hai unamein sankraman taap uchchatam hota hai aur atichaalakata ka gun bhi utkrusht hota hai.

anukram

pramukh atichaalak padaarth

dhaatu	T_C [K]	T_C [°aC]
Al	1,2	-271,95
In	3,4	-269,75
Sn	3,7	-269,45
Hg	4,2	-268,95
Ta	4,5	-268,65
V	5,4	-267,75
Pb	7,2	-265,95
Nb	9,3	-263,85

padaarth prakaar kraantik taap Tc(K)
jasta (Zinc) dhaatu (metal) 0.88
alamuniym (Aluminum) dhaatu (metal) 1.19
tin (Tin) dhaatu (metal) 3.72
paara (Mercury) dhaatu (metal) 4.15
YBa2Cu3O7 siraamik (ceramic) 90
TlBaCaCuO siraamik (ceramic) 125

atichaalakata ke upayog

1) bahut adhik chumbakeeya kshetr teevrata vaale chumbak (jaise 10 tesla) banaane ke liye atichaalak taaron ka prayog kiya jaata hai. inhein atichaalak chumbak kaate hain. inka upayog kan tvarakon mein hota hai.

2) bhavishya mein inka upayog chhote evam adhik kaaryadaksh traansafaarmar, motor, vidyut janitr, aadi banaane mein kiya ja sakta hai.

3) atichaalakon ka upayog skvid (SQUIDs ke nirmaan mein hota hai jo sarvaadhik samvedansheel chumbakeeya-kshetr-maapi hain.

4) inka upayog oorja ke bhandaaran ke liye kiya ja sakega kyonki kisi atichaalak loop mein ek baar dhaara sthaapit karke chhod dene par vah anant kaal tak chalti rahegi.

5) iska upayog maiganetik laiviteshan (magnetic lavitation) mein kiya ja sakega.

6) inke atirikt atichaalak traansamishn laaine, vidyutachumbak, radio-aavrutti kaiviti, atichaalak traanjistar, atichaalak ilektraun-punj leins (suparatrauni), atichaalak beeyaring, bolomeetar (ek vikirn sansoochak yukti), aadi mein bhi atichaalakata ka prayog ho raha hai.

atichaalakata ke prakaar

mukhya lekh : atichaalakon ka vargeekaran

parichay evam itihaas

atichaalakata ka kaalakram

jab koi dhaatu kisi upayukt aakaar mein, jaise belan athva taar ke roop mein li jaati hai, tab vah vidyut ke pravaah mein kuchh na kuchh pratirodh avashya utpann karti hai. kintu sarvapratham san 1911 mein kemaraling ons ne ek sanasaneepoorn khoj ki ki yadi paare ko 4 degree (param taap) ke neeche thandha kar diya jaae to usaka vidyuteeya pratirodh akasmaat nasht hokar vah poorn suchaalak ban jaata hai. lagbhag 20 dhaatuon mein, jinmein raaainga, paara, seesa ityaadi pramukh hain, yeh gun paaya jaata hai. jis taap ke neeche yeh dasha praapt hoti hai us taap ko sankraman taap (traijishn teinparechar) kehte hain aur is dasha ki chaalakata ko atichaalakata. sankraman taap na keval bhinn-bhinn dhaatuon ke liye pruthak-pruthak hote hain, apitu ek hi dhaatu ke vibhinn samasthaanikon ke liye bhi vibhinn hote hain. pailediym ainteemani jaise kai mishr dhaatuon mein bhi atichaalakata gun paaya jaata hai.

parmaanu mein ilektraun andaakaar path mein parikrama karte hain aur is drushti se ve chunbak jaisa kaarya karte hain. baahari chunbakeeya kshetr se in chunbakon ka aaghoorn (momeint) kam ho jaata hai. doosare shabdon mein, parmaanu visham chunbakeeya prabhaav dikhaate hain. yadi taap taas kisi padaarth ko upayukt chunbakeeya kshetr mein rakha jaae to us suchaalak ka aantarik chunbakeeya kshetr nasht ho jaata hai, arthaat vah ek visham chunbakeeya padaarth jaisa kaarya karne lagta hai. talaprushth par bahne waali vidyut dhaaraaon ke kaaran aantarik kshetr ka maan shoonya hi rahata hai. ise maaisanar ka prabhaav kehte hain. yadi atichaalak padaarth ko dheere-dheere badhne vaale chunbakeeya kshetr mein rakha jaae to kshetr ke ek vishesh maan par, jise dehali maan (threshold vailyoo) kehte hain, iska pratirodh pun: apne poorv maan ke baraabar ho jaata hai.

atichaalakata ki vyaakhya evam siddhaant

atichaalakata ke siddhaant ko samajhaane ke liye kai sujhaav diye gaye hain. kintu inmein se adhikaansh ko keval aanshik safalta hi praapt hui hai. vartamaan kaal mein baardeen, koopar tatha shreefar dvaara diya gaya siddhaant paryaapt santoshaprad hai. iska sankshipt naam vi.si.S. siddhaant hai. iske anusaar atichaalakata chaalak ilektraunon ke yugman se utpann hoti hai. yeh yugman ilektraunon ke beech aakarshak bal utpann ho jaane se paida hota hai. aakarshak bal utpann hone ka mukhya kaaran fonaan ya jaalak kapanon (laitis vaaibreshan) ka abhaasi vinimay (varachual exchange) hai.

inhein bhi dekhein

naayobiym - naayobiym-taaiteniym mishradhaatu ke bane taar atichaalak vidyutachumbak banaane mein kaam aate hain.