納米軟磁鐵氧體低頻磁導(dǎo)率的測(cè)量論文

1、東 南 大 學(xué)物 理 實(shí) 驗(yàn) 報(bào) 告姓 名 林海 學(xué) 號(hào) 10309102 指導(dǎo)教師 寇朝霞 日 期 2012-04-06 座位號(hào) 報(bào)告成績(jī) 實(shí)驗(yàn)名稱(chēng) 納米軟磁鐵氧體低頻磁導(dǎo)率的測(cè)量 一實(shí)驗(yàn)?zāi)康?、了解交變磁場(chǎng)下鐵磁物質(zhì)的磁性質(zhì)2、測(cè)量磁性納米顆粒復(fù)數(shù)磁導(dǎo)率3、對(duì)比納米尺度和大塊體材料的區(qū)別二實(shí)驗(yàn)原理在交變磁場(chǎng)的作用下，鐵磁物質(zhì)的磁性質(zhì)與它在靜磁場(chǎng)作用下的磁性質(zhì)有很大不同。首先，在靜磁場(chǎng)中，鐵磁材料的磁導(dǎo)率是一實(shí)數(shù)，但是在交變磁場(chǎng)中，由于存在磁滯效應(yīng)、渦流效應(yīng)、磁后效、疇壁共振、自然共振等，它在交變磁場(chǎng)中的磁感應(yīng)強(qiáng)度比外加的交變磁場(chǎng)落后一個(gè)相位，因而其磁導(dǎo)率是一復(fù)數(shù)。其次，各向同性的鐵磁物質(zhì)在

2、交變磁場(chǎng)中的復(fù)數(shù)磁導(dǎo)率不僅隨外磁場(chǎng)的幅值和外加磁場(chǎng)的頻率變化，而且在不同的頻段，決定復(fù)數(shù)磁導(dǎo)率的物理機(jī)制也是很不同的。再次，各項(xiàng)同性的鐵磁物質(zhì)在交變場(chǎng)中（尤其是在高頻交變場(chǎng)中）往往處于交變磁場(chǎng)和交變電場(chǎng)的同時(shí)作用，而鐵磁物質(zhì)又往往也是電介質(zhì)（例如鐵氧體），因而處在交變場(chǎng)中的鐵磁物質(zhì)往往同時(shí)顯示其鐵磁性和介電性。將交變磁場(chǎng)加在各向同性的鐵磁物質(zhì)上，交變磁場(chǎng)為： （1）由于存在阻礙磁矩運(yùn)動(dòng)的各種阻尼作用，磁感應(yīng)強(qiáng)度B將落后于外加磁場(chǎng)H某一相位角： （2）則該磁鐵物質(zhì)在交變磁場(chǎng)中的復(fù)數(shù)磁導(dǎo)率為：其中， （3）由于復(fù)數(shù)磁導(dǎo)率虛部的存在，使得磁感應(yīng)強(qiáng)度落后于外加磁場(chǎng)，這將引起鐵磁物質(zhì)在交變磁化過(guò)程中不斷

3、消耗外加能量。處于均勻交變磁場(chǎng)中的單位體積的鐵磁體，單位時(shí)間的平均能量損耗（稱(chēng)為磁損耗功率密度）為：可見(jiàn)單位體積的鐵磁體內(nèi)的磁損耗功率與復(fù)數(shù)磁導(dǎo)率的虛部構(gòu)成正比，與實(shí)部無(wú)關(guān)，而實(shí)部與它在交變磁場(chǎng)中的儲(chǔ)能密度有關(guān)。通常希望高，低，但是有些場(chǎng)合，如吸收式雷達(dá)隱身、波阻抗匹配降低反射率，反倒希望高些，甚至希望。在低頻弱磁場(chǎng)時(shí)，相應(yīng)于穩(wěn)恒磁場(chǎng)中所測(cè)定的起始磁導(dǎo)率，但是隨著頻率升高，與就有著明顯的差別。磁導(dǎo)率隨頻率變化的現(xiàn)象稱(chēng)為磁譜。通常，隨著頻率 升高，磁導(dǎo)率下降，達(dá)到某一截止頻率時(shí)，急劇下降，而急劇上升。通常定義下降到時(shí)所對(duì)應(yīng)的頻率為截止頻率。這就限制了軟磁材料使用頻率的上限。截止頻率的高低主要取決

4、于疇壁位移的弛豫與共振，以及磁疇轉(zhuǎn)動(dòng)所致的自然振動(dòng)。將待測(cè)樣品制成環(huán)狀，在其上面均勻繞城螺旋環(huán)。環(huán)形磁芯實(shí)際上可以等效為一個(gè)純電感和一個(gè)損耗電阻的串聯(lián)電路，或是并聯(lián)電路。這里我們用等效串聯(lián)電路。通過(guò)電動(dòng)力學(xué)和電磁學(xué)的知識(shí)，我們知道繞組中磁感應(yīng)強(qiáng)度是繞組兩端電壓U的函數(shù)，環(huán)形繞圈中的磁場(chǎng)是電流的函數(shù)。于是我們可以推導(dǎo)出磁芯線(xiàn)圈的阻抗和磁感應(yīng)強(qiáng)度，磁場(chǎng)的函數(shù)關(guān)系。進(jìn)而得出磁芯線(xiàn)圈的復(fù)數(shù)磁導(dǎo)率的電感和損耗電阻的函數(shù)。通過(guò)4284A型精密LCR測(cè)量?jī)x可以測(cè)出磁芯線(xiàn)圈的電感和損耗電阻，利用復(fù)數(shù)磁導(dǎo)率和、的關(guān)系式可以得出磁導(dǎo)率的實(shí)部和虛部。三實(shí)驗(yàn)步驟1、閱讀4284A型精密阻抗儀的說(shuō)明書(shū)，了解其面板及各按

5、鈕的功能；2、將測(cè)試引線(xiàn)短接、調(diào)零；3、將待測(cè)材料通過(guò)測(cè)試引線(xiàn)連接；4、選擇“More 3/6”，選擇：LsRs模式；5、移動(dòng)光標(biāo)至“FREQ”字段，使用INCR ，從20Hz到1MHz，記錄數(shù)據(jù)。6、將數(shù)據(jù)輸入計(jì)算機(jī)，處理后，用Origin繪出關(guān)系圖。四實(shí)驗(yàn)數(shù)據(jù)處理及分析根據(jù)公式和選取參數(shù)，使得，將三種樣品的參數(shù)a計(jì)算如表一。表一 三種樣品的參數(shù)a匝數(shù)N高度h/mm外徑r2/mm內(nèi)徑r1/mma/H鈣鈦礦604.115.36.62.481991945錳鋅鐵氧體769.925.114.726.103200298四氧化三鐵666.220103.743992907代入源數(shù)據(jù)，則有表二。表二(1)

6、鈣鈦礦的復(fù)數(shù)磁導(dǎo)率測(cè)量值表頻率/HzLs/HRs/200.224960.000010.0906368780.20145109725-0.31530.00006-0.1270350620.966965265301.8518400.7461103990400.428940.000240.1728208672.417413163500.715450.000140.2882563751.128126143600.48181-0.000060.194122306-0.402902194800.225010.000090.0906570230.453264968100-0.069730.0001-0.02

7、8094370.4029021941200.144320.00010.0581468450.335751828150-0.087140.00011-0.0351088970.295461609200-0.035730.0001-0.0143956950.2014510972500.000350.000350.0001410160.5640630713000.00010.00014.02902E-050.1343007314000.020110.000030.0081023630.0302176655000.004020.00010.0016196670.080580439600-0.00562

8、0.00016-0.002264310.1074405858000.006030.000130.00242950.06547160710000.003420.00030.0013779260.12087065812000.008120.000070.0032715660.02350262815000.0020.000080.0008058040.02148811720000.005750.000120.0023166880.02417413225000.004050.000130.0016317540.02095091430000.004320.000140.0017405370.018802

9、10240000.004320.000130.0017405370.01309432150000.005450.000170.0021958170.01369867560000.009050.000070.0036462650.00470052680000.00730.000120.0029411860.00604353310000-0.01282.23342-0.00515714889.98498178120000.008520.000360.0034327270.012087066150000.008310.000380.0033481170.010206856200000.00620.0

10、00180.0024979940.00362612250000.0063-0.00040.002538284-0.006446435300000.0065-0.000010.002618864-0.000134301400000.00810.000130.0032635080.001309432500000.00405-0.002330.001631754-0.018775242600000.1275-0.007850.05137003-0.052713037800000.07064-0.745650.028461011-3.755300261100000-0.49312-1.53032-0.

11、19867913-6.1656928531200000.36089-0.456810.145403373-1.533747927150000-0.429940.47819-0.1732237691.284425334200000-0.844770.72646-0.3403596861.463461639250000-1.220230.76141-0.4916333441.227095038300000-1.815880.87109-0.7316220361.16988024400000-3.1759-3.46859-1.279577078-3.493756302500000-0.3647-12

12、.2691-0.14693843-9.8864946146000001.01738-7.787350.409904634-5.2292339998000000.77922-4.043150.313949448-2.03624250610000000.50945-2.130680.205258523-0.858455646表二(2) 錳鋅鐵氧體的復(fù)數(shù)磁導(dǎo)率測(cè)量值表頻率/HzLs/HRs/200.224960.000010.0906368780.20145109725-0.31530.00006-0.1270350620.966965265301.8518400.7461103990400.428

13、940.000240.1728208672.417413163500.715450.000140.2882563751.128126143600.48181-0.000060.194122306-0.402902194800.225010.000090.0906570230.453264968100-0.069730.0001-0.028094370.4029021941200.144320.00010.0581468450.335751828150-0.087140.00011-0.0351088970.295461609200-0.035730.0001-0.0143956950.2014

14、510972500.000350.000350.0001410160.5640630713000.00010.00014.02902E-050.1343007314000.020110.000030.0081023630.0302176655000.004020.00010.0016196670.080580439600-0.005620.00016-0.002264310.1074405858000.006030.000130.00242950.06547160710000.003420.00030.0013779260.12087065812000.008120.000070.003271

15、5660.02350262815000.0020.000080.0008058040.02148811720000.005750.000120.0023166880.02417413225000.004050.000130.0016317540.02095091430000.004320.000140.0017405370.01880210240000.004320.000130.0017405370.01309432150000.005450.000170.0021958170.01369867560000.009050.000070.0036462650.00470052680000.00

16、730.000120.0029411860.00604353310000-0.01282.23342-0.00515714889.98498178120000.008520.000360.0034327270.012087066150000.008310.000380.0033481170.010206856200000.00620.000180.0024979940.00362612250000.0063-0.00040.002538284-0.006446435300000.0065-0.000010.002618864-0.000134301400000.00810.000130.003

17、2635080.001309432500000.00405-0.002330.001631754-0.018775242600000.1275-0.007850.05137003-0.052713037800000.07064-0.745650.028461011-3.755300261100000-0.49312-1.53032-0.19867913-6.1656928531200000.36089-0.456810.145403373-1.533747927150000-0.429940.47819-0.1732237691.284425334200000-0.844770.72646-0

18、.3403596861.463461639250000-1.220230.76141-0.4916333441.227095038300000-1.815880.87109-0.7316220361.16988024400000-3.1759-3.46859-1.279577078-3.493756302500000-0.3647-12.2691-0.14693843-9.8864946146000001.01738-7.787350.409904634-5.2292339998000000.77922-4.043150.313949448-2.03624250610000000.50945-

19、2.130680.205258523-0.858455646表二(3) 四氧化三鐵的復(fù)數(shù)磁導(dǎo)率測(cè)量值表頻率/HzLs/HRs/10000000.43053-2.599170.114992205-0.6942240728000000.06437-1.752620.017192874-0.585144004600000-0.576850.94305-0.1540734760.419805817500000-0.671723.98103-0.1794127332.1266226194000000.736742.734040.1967792191.8256177753000000.556150.247

20、870.1485446190.2206823982500000.55345-0.16360.147823464-0.1747866562000000.3364-0.156660.089850598-0.209215141500000.13312-0.052040.035555623-0.0926639931200000.2393-0.239580.063915719-0.533254215100000-0.4828-1.61193-0.128953236-4.305376746800000.039320.265280.0105021570.885685439600000.024380.0012

21、30.0065117640.005475438500000.001920.000040.0005128210.000213676400000.00445-0.000050.001188571-0.000333868300000.0052-0.000060.001388892-0.000534189250000.00567-0.000070.001514426-0.000747865200000.0057800.0015438060150000.006040.000130.0016132510.002314819120000.00570.000130.0015224390.00289352410

22、000-0.010720.00018-0.0028632530.00480770180000.006810.000070.0018189140.00233707760000.007420.000050.0019818410.00222578850000.00650.000080.0017361140.00427351240000.00480.000060.0012820540.00400641830000.005850.000070.0015625030.00623220625000.007130.000070.0019043840.00747864720000.009060.000080.0

23、024198760.01068378115000.005440.000040.0014529940.00712252112000.008320.000030.0022222260.00667736310000.006950.000260.0018563070.0694445768000.002560.000070.0006837620.0233707716000.01080.000150.0028846210.0667736315000.019910.000040.0053178520.0213675624000.02234-0.000030.005966892-0.020032089300-0.024070.00006-0.0064289650.053418905250-0.048040.00011-0.0128312210.11752159200-0.014220.00009-0.0037980840.120192535150-0.057450.00001-0.015344580.0178063021200.1638900.0437741210100-0.017520.0001-0.004