121:
17:
248:, Permalloy is often used in applications that require efficient magnetic field generation and sensing. This nickel-iron magnetic alloy, typically composed of about 80% nickel and 20% iron, exhibits low energy loss, which is beneficial for improving the performance of magnetic sensors,
140:
were laid in the 1860s, it was found that the long conductors caused distortion which reduced the maximum signalling speed to only 10–12 words per minute. The right conditions for transmitting signals through cables without distortion were first worked out mathematically in 1885 by
81:. The low magnetostriction is critical for industrial applications, allowing it to be used in thin films where variable stresses would otherwise cause a ruinously large variation in magnetic properties. Permalloy's electrical
157:
to reduce distortion. However, iron did not have high enough permeability to compensate a transatlantic-length cable. After a prolonged search, permalloy was discovered in 1914 by
93:
crystal structure with a lattice constant of approximately 0.355 nm in the vicinity of a nickel concentration of 80%. A disadvantage of permalloy is that it is not very
256:. Permalloy is also used in the production of magnetic shielding materials, which help protect electronic equipment from external magnetic interference.
228:, at 79% Ni, 16% Fe, and 5% Mo, is also well known for its high performance as a "soft" magnetic material, characterized by high permeability and low
158:
60:
506:"Measurement and Analysis of Magnetic Properties of Permalloy for Magnetic Shielding Devices under Different Temperature Environments"
224:
in 1940. At the time, when used in long distance copper telegraph lines, it allowed a tenfold increase in maximum line working speed.
97:
or workable, so applications requiring elaborate shapes, such as magnetic shields, are made of other high permeability alloys such as
353:
176:
This method of cable compensation declined in the 1930s, but by World War II many other uses for
Permalloy were found in the
590:
575:
488:
454:
616:
188:
Other compositions of permalloy are available, designated by a numerical prefix denoting the weight percentage of
241:
343:
173:. A wrapping of permalloy tape could reportedly increase the signalling speed of a telegraph cable fourfold.
40:
149:
in 1902 in
Denmark that the cable could be compensated by wrapping it with iron wire, increasing the
137:
611:
479:
Gale, W.F.; Totemeier, T.C., eds. (2004). "Chapter 20 - Magnetic materials and their properties".
606:
39:, with about 80% nickel and 20% iron content. Invented in 1914 by physicist Gustav Elmen at
44:
517:
417:
177:
305:
8:
90:
540:
521:
505:
375:
455:"The role of soft magnetic powder in technology : identification and applications"
433:
321:
52:
120:
586:
571:
545:
484:
349:
162:
78:
535:
525:
429:
317:
146:
142:
71:
85:
can vary as much as 5% depending on the strength and the direction of an applied
170:
109:
86:
56:
600:
166:
105:
48:
549:
265:
249:
169:. Later, in 1923, he found its permeability could be greatly enhanced by
280:
225:
154:
102:
82:
75:
66:
In addition to high permeability, its other magnetic properties are low
530:
245:
229:
217:
150:
133:
129:
67:
253:
221:
94:
63:
of around 100,000, compared to several thousand for ordinary steel.
270:
98:
16:
275:
128:
Permalloy was initially developed in the early 20th century for
483:(Eighth ed.). Butterworth-Heinemann. pp. 20-1–20-24.
209:
197:
189:
28:
306:"Permalloy, A New Magnetic Material of Very High Permeability"
205:
193:
51:
material in electrical and electronic equipment, and also in
36:
376:"150 Years Of Industry & Enterprise At Enderby's Wharf"
213:
201:
196:, for example "45 permalloy" means an alloy containing 45%
32:
380:
History of the
Atlantic Cable and Undersea Communications
124:
Submarine telegraph cable wrapped with permalloy tape.
283:(a material with even higher magnetic permeability)
303:
598:
345:Introduction to Magnetism and Magnetic Materials
406:(London: G. Bell & Sons, 1943) pp. 212–213.
59:. Commercial permalloy alloys typically have
478:
428:(1). USA: American Tel. & Tel.: 113–135.
418:"Magnetic Alloys of Iron, Nickel, and Cobalt"
316:(3). USA: American Tel. & Tel.: 101–111.
165:, who found it had higher permeability than
539:
529:
585:Institute of Physics Publishing (1992),
204:by weight. "Molybdenum permalloy" is an
119:
15:
398:
396:
369:
367:
365:
304:Elmen, G.W.; H. D. Arnold (July 1923).
299:
297:
599:
503:
136:cables. When the first transatlantic
581:P. Ciureanu and S. Middelhoek, eds.,
415:
409:
373:
341:
183:
393:
362:
335:
294:
13:
434:10.1002/j.1538-7305.1936.tb00721.x
322:10.1002/j.1538-7305.1923.tb03595.x
43:, it is notable for its very high
14:
628:
570:Wiley-IEEE Press (1993 reissue),
89:. Permalloys typically have the
481:Smithells Metals Reference Book
235:
497:
472:
447:
115:
1:
560:
220:. The latter was invented at
47:, which makes it useful as a
583:Thin Film Resistive Sensors,
416:Elmen, G.W. (January 1936).
7:
459:Stanford Advanced Materials
259:
41:Bell Telephone Laboratories
10:
633:
348:. CRC Press. p. 354.
138:submarine telegraph cables
504:Sun, J.; Ren, J. (2023).
240:Due to its high magnetic
287:
101:. Permalloy is used in
617:Ferromagnetic materials
145:. It was proposed by
125:
21:
374:Green, Allen (2004).
342:Jiles, David (1998).
123:
61:relative permeability
45:magnetic permeability
19:
566:Richard M. Bozorth,
178:electronics industry
522:2023Mate...16.3253S
422:Bell System Tech. J
310:Bell System Tech. J
91:face-centered cubic
531:10.3390/ma16083253
184:Other compositions
126:
74:, and significant
53:magnetic shielding
22:
20:Strip of permalloy
355:978-0-412-79860-3
163:Bell Laboratories
79:magnetoresistance
624:
554:
553:
543:
533:
501:
495:
494:
476:
470:
469:
467:
465:
451:
445:
444:
442:
440:
413:
407:
400:
391:
390:
388:
387:
371:
360:
359:
339:
333:
332:
330:
328:
301:
153:and making it a
147:Carl Emil Krarup
143:Oliver Heaviside
132:compensation of
72:magnetostriction
632:
631:
627:
626:
625:
623:
622:
621:
612:Magnetic alloys
597:
596:
568:Ferromagnetism,
563:
558:
557:
502:
498:
491:
477:
473:
463:
461:
453:
452:
448:
438:
436:
414:
410:
401:
394:
385:
383:
372:
363:
356:
340:
336:
326:
324:
302:
295:
290:
262:
238:
186:
118:
110:recording heads
57:magnetic fields
12:
11:
5:
630:
620:
619:
614:
609:
595:
594:
579:
562:
559:
556:
555:
496:
489:
471:
446:
408:
392:
361:
354:
334:
292:
291:
289:
286:
285:
284:
278:
273:
268:
261:
258:
237:
234:
185:
182:
171:heat treatment
117:
114:
87:magnetic field
9:
6:
4:
3:
2:
629:
618:
615:
613:
610:
608:
607:Nickel alloys
605:
604:
602:
592:
591:0-7503-0173-2
588:
584:
580:
577:
576:0-7803-1032-2
573:
569:
565:
564:
551:
547:
542:
537:
532:
527:
523:
519:
515:
511:
507:
500:
492:
490:9780750675093
486:
482:
475:
460:
456:
450:
435:
431:
427:
423:
419:
412:
405:
399:
397:
381:
377:
370:
368:
366:
357:
351:
347:
346:
338:
323:
319:
315:
311:
307:
300:
298:
293:
282:
279:
277:
274:
272:
269:
267:
264:
263:
257:
255:
251:
247:
243:
233:
231:
227:
223:
219:
215:
211:
207:
203:
199:
195:
191:
181:
179:
174:
172:
168:
167:silicon steel
164:
160:
156:
152:
148:
144:
139:
135:
131:
122:
113:
111:
108:and magnetic
107:
104:
100:
96:
92:
88:
84:
80:
77:
73:
69:
64:
62:
58:
54:
50:
49:magnetic core
46:
42:
38:
34:
30:
26:
18:
582:
567:
513:
509:
499:
480:
474:
462:. Retrieved
458:
449:
437:. Retrieved
425:
421:
411:
403:
384:. Retrieved
382:. FTL Design
379:
344:
337:
325:. Retrieved
313:
309:
266:Loading coil
250:transformers
242:permeability
239:
236:Applications
187:
175:
159:Gustav Elmen
127:
70:, near zero
65:
24:
23:
516:(8): 3253.
439:December 6,
404:Electricity
327:December 6,
281:Supermalloy
226:Supermalloy
155:loaded line
116:Development
106:laminations
103:transformer
83:resistivity
76:anisotropic
601:Categories
561:References
402:Bragg, L.
386:2008-12-14
246:coercivity
230:coercivity
218:molybdenum
200:, and 55%
151:inductance
68:coercivity
510:Materials
254:inductors
222:Bell Labs
134:telegraph
130:inductive
55:to block
35:magnetic
25:Permalloy
550:37110086
541:10145743
464:July 15,
271:Mu-metal
260:See also
244:and low
99:mu metal
518:Bibcode
276:Sendust
216:and 2%
208:of 81%
192:in the
95:ductile
589:
574:
548:
538:
487:
352:
252:, and
212:, 17%
210:nickel
198:nickel
190:nickel
29:nickel
288:Notes
206:alloy
194:alloy
37:alloy
27:is a
587:ISBN
572:ISBN
546:PMID
485:ISBN
466:2024
441:2012
350:ISBN
329:2012
214:iron
202:iron
33:iron
536:PMC
526:doi
430:doi
318:doi
161:of
603::
544:.
534:.
524:.
514:16
512:.
508:.
457:.
426:15
424:.
420:.
395:^
378:.
364:^
312:.
308:.
296:^
232:.
180:.
112:.
593:.
578:.
552:.
528::
520::
493:.
468:.
443:.
432::
389:.
358:.
331:.
320::
314:2
31:–
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
