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Stroboscopic topographies on iron borate crystal in 9.6 MHz rf magnetic field
Nuclear Instruments and Methods in Physics Research B 199 (2003) 75–80 www.elsevier.com/locate/nimb
Stroboscopic topographies on iron borate crystal in 9.6 MHz rf magnetic field Takaya Mitsui b
a,*
, Yasuhiko Imai b, Seishi Kikuta
b
a Japan Atomic Energy Research Institute, Kamigori, Ako-gun, Hyogo 678-12, Japan Japan Synchrotron Radiation Research Institute, 1-1-1 Mikazuki-cho, Sayo-gun, Hyogo 679-5198, Japan
Abstract The influence of magnetoacoustic wave on the crystal deformation was studied by stroboscopic double crystal X-ray topography. The acoustic wave was excited by the rf magnetic field, which was synchronized with synchrotron radiation X-ray pulse. In measured rocking curves of FeBO3 (4 4 4) reflection, we observed, for the first time, that the application of rf magnetic field (jHrf jmax > 8:4 Oe) brought about the extreme narrowing of full width at half maximum (FWHM). Recorded topographs showed that the narrowing of FWHM was due to the magnetoacoustic standing wave which is excited in FeBO3 crystal. In our experiments, the influence of additional static magnetic field on the magnetoacoustic standing wave of FeBO3 crystal was investigated too. Ó 2002 Elsevier Science B.V. All rights reserved. PACS: 72.55.+s; 75.80.+q; 75.90.+w Keywords: Synchrotron radiation; Stroboscopic X-ray topography; Magnetoacoustic wave; FeBO3 single crystal
1. Introduction The antiferromagnet iron borate (FeBO3 ) single crystal (TN ¼ 348:5 K) has a calcite structure and it shows a good transparency in the visible region of the spectrum [1–3]. Recently, from the viewpoints of fundamental physics research, many scientists have paid attention to the acoustic vibration phe-
* Corresponding author. Address: Japan Atomic Energy Research Institute, Kansai Research Establishment, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148, Japan. Tel.: +81-791-58-2701; fax: +81-791-58-2740. E-mail address: [email protected] (T. Mitsui).
nomenon of FeBO3 crystal, which is exposed to rf magnetic field or ultrasonic wave. Because, in such nonequilibrium systems, this crystal holds promise for the observation of nonlinear effects [4–6], and even magnetoacoustic solitons [7]. In addition, from the viewpoints of application research, the acoustic vibration phenomenon of FeBO3 single crystal is very useful for X-ray active optical element [8]. Therefore, the influence of acoustic vibration on the crystal deformation of FeBO3 single crystal is a very important research subject. Recently, in order to investigate the subject, we carried out stroboscopic double crystal X-ray topography by using single bunch mode of synchrotron radiation (SR). Then, the acoustic
0168-583X/02/$ - see front matter Ó 2002 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X ( 0 2 ) 0 1 4 1 3 - 1
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T. Mitsui et al. / Nucl. Instr. and Meth. in Phys. Res. B 199 (2003) 75–80
vibration of FeBO3 crystal was excited by rf magnetic field synchronized with SR X-ray pulse. In this paper, the experimental set-up and results are reported.
2. Experimental set-up The experiments were performed at the BL-14B at Photon Factory (KEK). The experimental set-up is shown in Fig. 1. The synchrotron beam was tuned to k ¼ 1:24 A by Si(1 1 1) double crystal monochromator, and was collimated by Si(4 0 0) asymmetric reflection (1=b ¼ 4:39, xh ¼ 1:35 arcs). The delivered X-ray beam then becomes parallel in comparison with the diffraction width of FeBO3 (4 4 4) Bragg reflection (xh ¼ 3:56 arcs), and these crystals fulfill a condition of () parallel setting. An external rf magnetic field was applied parallel to FeBO3 (1 1 1) plane and perpendicular to scattering plane with various peak amplitudes (0–16.8 Oe) and frequency of 9.61728 MHz. The frequency was six times as large as the frequency of SR X-ray pulse (1.60288 MHz) exactly. In phase locking, the timing of SR X-ray incidence was fixed in the phase of zero amplitude of rf magnetic field for all measurements (see Fig. 1). The additional static magnetic field was applied parallel to FeBO3 (1 1 1) plane and scattering plane with various strengths (0–25 Oe).
Fig. 2. Rocking curves of FeBO3 (4 4 4) reflection placed in external rf magnetic fields; Hrf : (a) 0.0 Oe, (b) 4.2 Oe, (c) 8.4 Oe, (d) 12.0 Oe, (e) 16.8 Oe.
Fig. 1. Optical arrangement for stroboscopic X-ray topography.
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Fig. 3. Stroboscopic topographs of FeBO3 (4 4 4) reflection placed in rf magnetic field. Topographs (a)–(e) are recorded at peak angles of each rocking curves of Fig. 2(a)–(e). Fig. 3(f) is the histogram as a function of the X coordinate on the topograph of Fig. 2(e).
3. Experimental results 3.1. Rocking curve of FeBO3 single crystal in Hrf with Hc ¼ 0 At first, the rocking curves of FeBO3 (4 4 4) reflection were measured with various strengths of rf magnetic field without static magnetic field. They are shown in Fig. 2. At the strength of rf magnetic field below 4.2 Oe (see Fig. 2(a) and (b)), the measured rocking curves show both sub-peaks and broad tails in a very large angular range (100 arcs). These results indicate that this FeBO3 crystal has some defects (misorientations between growth boundaries and crystal bent) in the range of 100 arcs. But, in
contrast, at the strength of rf magnetic field over 8.4 Oe, the rocking curves change into a sharp form of single peak abruptly. At the same time, strong narrowing of full width at half maximum (FWHM) and enhancement of peak intensity are caused (see Fig. 2(c)). Finally, the value of FWHM reaches to 8.0 arcs (see Fig. 2(d) and (e)). This value is the same order of theoretical the value (the intrinsic FWHM of FeBO3 (4 4 4) reflection is ). about 4.0 arcs at k ¼ 1:24 A 3.2. Strobo X-ray topography of FeBO3 single crystal in Hrf with Hc ¼ 0 In order to investigate the origin of the narrowing of FWHM, stroboscopic X-ray topographs
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T. Mitsui et al. / Nucl. Instr. and Meth. in Phys. Res. B 199 (2003) 75–80
were recorded at the peak positions of each rocking curves of Fig. 2(a)–(e). These topographs are shown in Fig. 3(a)–(e), respectively. In topographs of sub-peak cases, X-ray diffraction contrasts are given as the uniform illuminations from small areas of FeBO3 crystal (see Fig. 3(a) and (b)). These contrasts reflect misorientations and bent of the FeBO3 crystal, and it is consistent with the result of rocking curve measurements. On the contrary, in topographs of single-peak cases, the contrasts change into a periodic black-and-white stripe pattern abruptly. Then, the X-ray illuminating area of FeBO3 (4 4 4) reflection increases considerably (see Fig. 3(c)–(e)). From the histogram of a dashed line part of Fig. 3(e), the distance between the nodes of magnetoacoustic standing wave was estimated to be 290 lm quantitatively (see Fig. 3(f)). These results imply that rf magnetic field over 8.4 Oe excites the acoustic standing wave in FeBO3 crystal, and it causes a striped deformation for FeBO3 crystal through magnetostrictive interaction [8]. As a noticeable effect, the excited magnetoacoustic standing wave repairs the collapse of the rocking curve due to the congenital defects of this FeBO3 single crystal. It may be a very important phenomenon for the futureÕs application researches. 3.3. Rocking curve of FeBO3 single crystal in Hrf , with Hc 6¼ 0 Secondly, in order to investigate the influence of static magnetic field on the magnetoacoustic standing wave of FeBO3 crystal, rocking curves of FeBO3 (4 4 4) reflection were measured with various strengths of static magnetic field; (Hc ¼ 0, 3, 6, 12, 25 Oe). The rocking curves are shown in Fig. 4. (In these measurements, the peak amplitude of rf magnetic field was fixed in 16.8 Oe.) As is shown in Fig. 4(a) and (b), at the strength of static magnetic field below 3.0 Oe, the measured rocking curves did not show noticeable changes, and they kept a sharp form of single-peak except for the slight broadening of FWHM (<2.0 arcs). However, at the strength of static magnetic field over 6.0 Oe, the rocking curve shows a strong broadening of FWHM and peak splitting abruptly. At the same time, the peak intensity shows a strong reduction
Fig. 4. Rocking curve of FeBO3 (4 4 4) reflaction placed in external magnetic fields; Hrf ¼ 16:8 Oe and Hc : (a) 0.0 Oe, (b) 3.0 Oe, (c) 6.0 Oe, (d) 12.0 Oe, (e) 25.0 Oe.
(see Fig. 4(c)). Finally, through the opposite process of the previous experimental results (see Fig. 2), the rocking curve goes back to the collapsed form of sub-peaks and broad tails (see Fig. 4(d) and (e)). From these results, we found that the static magnetic filed could destroy the sharpness of the rocking curve, which was realized by exposing rf magnetic field, and the noticeable transformation of rocking curve broke out in a specific range of 3.0–6.0 Oe. In the viewpoint of practical applications, this broadening effects is also very interesting as well as narrowing of FWHM. Because, our experimental result indicates that the shape of
T. Mitsui et al. / Nucl. Instr. and Meth. in Phys. Res. B 199 (2003) 75–80
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Fig. 5. Stroboscopic topographs of FeBO3 (4 4 4) reflection placed in rf magnetic field and static magnetic fields. All topographs are recorded at peak angles of rocking curves of Fig. 4(a)–(d). Fig. 5(e) is the histogram as a function of the X coordinate on the topograph of Fig. 5(b).
rocking curve of FeBO3 crystal can be controlled by only an weak static magnetic field; Hc < 12 Oe. For example, this property may realize a function of X-ray optical shutter element. 3.4. Strobo X-ray topography of FeBO3 single crystal in Hrf with Hc 6¼ 0 The interrelation between broadening of FWHM and magnetoacoustic standing wave of FeBO3 crystal was investigated by stroboscopic Xray topography. The topographs were recorded at the peak positions of each rocking curves of Fig. 4(a)–(d) and they are shown in Fig. 5(a)–(d) re-
spectively. As is shown in Fig. 5(a) and (b), both topographs of single-peak cases show the periodic black-and-white stripe patterns. But, from the histogram of a dashed line part of Fig. 5(b), the distance between the nodes of magnetoacoustic standing wave is about 170 lm (see Fig. 5(e)). That value is short in comparing with the case of Hrf and Hc ¼ 0 Oe (see Fig. 3(e)), and it demonstrates that the applying of weak static magnetic field of merely 3.0 Oe affects the magnetoacoustic vibrating mode of FeBO3 crystal very sensitively. On the contrary, the topographs of sub-peaks cases recorded with the static magnetic field over 6.0 Oe show the completely disappearance of the
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magnetoacoustic standing wave (see Fig. 4(c) and (d)), and the X-ray diffraction contrasts change into a uniform illuminations from small areas of FeBO3 crystal surface by the regeneration of misorientations and bent. From the results of rocking curve and stroboscopic topographs, we can draw the conclusion that the disappearance of magnetoacoustic standing wave is connected to the broadening of FWHM.
standing wave of FeBO3 crystal play an important key role in the narrowing and the broadening of FWHM respectively.
Acknowledgements The authors are grateful to H. Takei for the FeBO3 single crystal, Y. Yoda and X.W. Zhang for fruitful discussions and T. Harami for a critical reading of the manuscript.
4. Summary To sum up, stroboscopic double crystal X-ray topography is a very suitable method for magnetoacoustic vibration of FeBO3 crystal. This method gives us many fruitful informations. In our cases, the rocking curves of FeBO3 (4 4 4) reflection showed that the extreme narrowing of FWHM took place at the strength of rf magnetic field over 8.4 Oe. On the contrary, the additional static magnetic field over 6.0 Oe led to the strong broadening of FWHM. In addition, the recorded stroboscopic topographs visualized the excited magnetoacoustic standing wave of FeBO3 crystal. As the results, we found that emergence and extinction of magnetoacoustic
References [1] M. Eibsch€ utz, M.E. Lines, Phys. Rev. B 7 (1973) 4907. [2] M. Pernet, D. Elmaleh, J.C. Joubert, Solid State Commun. 8 (1970) 1593. [3] R. Diehl, Solid State Commun. 17 (1975) 743. [4] M.V. Chetkin, V.V. Lykov, JETP Lett. 52 (1990) 235. [5] L.E. Svistov, V.L. Safonov, L. L€ ow, H. Benner, J. Phys.: Condens. Matt. 6 (1994) 8051. [6] Q.Z. Zhang, M. Mino, V.L. Safonov, H. Yamazaki, J. Phys. Soc. Jpn. 69 (2000) 41. [7] V.I. Ozhogin, V.L. Preobrazhenskii, USP Fiz. Nauk. 155 (1988) 539 (Sov. Phys. USP 31 (1988) 713). [8] L. Matsouli, V. Kvardakov, J. Espeso, L. Chabert, J. Baruchel, J. Phys. D: Appl. Phys. 31 (1998) 1478.
Stroboscopic topographies on iron borate crystal in 9.6 MHz rf magnetic field Takaya Mitsui b
a,*
, Yasuhiko Imai b, Seishi Kikuta
b
a Japan Atomic Energy Research Institute, Kamigori, Ako-gun, Hyogo 678-12, Japan Japan Synchrotron Radiation Research Institute, 1-1-1 Mikazuki-cho, Sayo-gun, Hyogo 679-5198, Japan
Abstract The influence of magnetoacoustic wave on the crystal deformation was studied by stroboscopic double crystal X-ray topography. The acoustic wave was excited by the rf magnetic field, which was synchronized with synchrotron radiation X-ray pulse. In measured rocking curves of FeBO3 (4 4 4) reflection, we observed, for the first time, that the application of rf magnetic field (jHrf jmax > 8:4 Oe) brought about the extreme narrowing of full width at half maximum (FWHM). Recorded topographs showed that the narrowing of FWHM was due to the magnetoacoustic standing wave which is excited in FeBO3 crystal. In our experiments, the influence of additional static magnetic field on the magnetoacoustic standing wave of FeBO3 crystal was investigated too. Ó 2002 Elsevier Science B.V. All rights reserved. PACS: 72.55.+s; 75.80.+q; 75.90.+w Keywords: Synchrotron radiation; Stroboscopic X-ray topography; Magnetoacoustic wave; FeBO3 single crystal
1. Introduction The antiferromagnet iron borate (FeBO3 ) single crystal (TN ¼ 348:5 K) has a calcite structure and it shows a good transparency in the visible region of the spectrum [1–3]. Recently, from the viewpoints of fundamental physics research, many scientists have paid attention to the acoustic vibration phe-
* Corresponding author. Address: Japan Atomic Energy Research Institute, Kansai Research Establishment, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148, Japan. Tel.: +81-791-58-2701; fax: +81-791-58-2740. E-mail address: [email protected] (T. Mitsui).
nomenon of FeBO3 crystal, which is exposed to rf magnetic field or ultrasonic wave. Because, in such nonequilibrium systems, this crystal holds promise for the observation of nonlinear effects [4–6], and even magnetoacoustic solitons [7]. In addition, from the viewpoints of application research, the acoustic vibration phenomenon of FeBO3 single crystal is very useful for X-ray active optical element [8]. Therefore, the influence of acoustic vibration on the crystal deformation of FeBO3 single crystal is a very important research subject. Recently, in order to investigate the subject, we carried out stroboscopic double crystal X-ray topography by using single bunch mode of synchrotron radiation (SR). Then, the acoustic
0168-583X/02/$ - see front matter Ó 2002 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X ( 0 2 ) 0 1 4 1 3 - 1
76
T. Mitsui et al. / Nucl. Instr. and Meth. in Phys. Res. B 199 (2003) 75–80
vibration of FeBO3 crystal was excited by rf magnetic field synchronized with SR X-ray pulse. In this paper, the experimental set-up and results are reported.
2. Experimental set-up The experiments were performed at the BL-14B at Photon Factory (KEK). The experimental set-up is shown in Fig. 1. The synchrotron beam was tuned to k ¼ 1:24 A by Si(1 1 1) double crystal monochromator, and was collimated by Si(4 0 0) asymmetric reflection (1=b ¼ 4:39, xh ¼ 1:35 arcs). The delivered X-ray beam then becomes parallel in comparison with the diffraction width of FeBO3 (4 4 4) Bragg reflection (xh ¼ 3:56 arcs), and these crystals fulfill a condition of () parallel setting. An external rf magnetic field was applied parallel to FeBO3 (1 1 1) plane and perpendicular to scattering plane with various peak amplitudes (0–16.8 Oe) and frequency of 9.61728 MHz. The frequency was six times as large as the frequency of SR X-ray pulse (1.60288 MHz) exactly. In phase locking, the timing of SR X-ray incidence was fixed in the phase of zero amplitude of rf magnetic field for all measurements (see Fig. 1). The additional static magnetic field was applied parallel to FeBO3 (1 1 1) plane and scattering plane with various strengths (0–25 Oe).
Fig. 2. Rocking curves of FeBO3 (4 4 4) reflection placed in external rf magnetic fields; Hrf : (a) 0.0 Oe, (b) 4.2 Oe, (c) 8.4 Oe, (d) 12.0 Oe, (e) 16.8 Oe.
Fig. 1. Optical arrangement for stroboscopic X-ray topography.
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Fig. 3. Stroboscopic topographs of FeBO3 (4 4 4) reflection placed in rf magnetic field. Topographs (a)–(e) are recorded at peak angles of each rocking curves of Fig. 2(a)–(e). Fig. 3(f) is the histogram as a function of the X coordinate on the topograph of Fig. 2(e).
3. Experimental results 3.1. Rocking curve of FeBO3 single crystal in Hrf with Hc ¼ 0 At first, the rocking curves of FeBO3 (4 4 4) reflection were measured with various strengths of rf magnetic field without static magnetic field. They are shown in Fig. 2. At the strength of rf magnetic field below 4.2 Oe (see Fig. 2(a) and (b)), the measured rocking curves show both sub-peaks and broad tails in a very large angular range (100 arcs). These results indicate that this FeBO3 crystal has some defects (misorientations between growth boundaries and crystal bent) in the range of 100 arcs. But, in
contrast, at the strength of rf magnetic field over 8.4 Oe, the rocking curves change into a sharp form of single peak abruptly. At the same time, strong narrowing of full width at half maximum (FWHM) and enhancement of peak intensity are caused (see Fig. 2(c)). Finally, the value of FWHM reaches to 8.0 arcs (see Fig. 2(d) and (e)). This value is the same order of theoretical the value (the intrinsic FWHM of FeBO3 (4 4 4) reflection is ). about 4.0 arcs at k ¼ 1:24 A 3.2. Strobo X-ray topography of FeBO3 single crystal in Hrf with Hc ¼ 0 In order to investigate the origin of the narrowing of FWHM, stroboscopic X-ray topographs
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T. Mitsui et al. / Nucl. Instr. and Meth. in Phys. Res. B 199 (2003) 75–80
were recorded at the peak positions of each rocking curves of Fig. 2(a)–(e). These topographs are shown in Fig. 3(a)–(e), respectively. In topographs of sub-peak cases, X-ray diffraction contrasts are given as the uniform illuminations from small areas of FeBO3 crystal (see Fig. 3(a) and (b)). These contrasts reflect misorientations and bent of the FeBO3 crystal, and it is consistent with the result of rocking curve measurements. On the contrary, in topographs of single-peak cases, the contrasts change into a periodic black-and-white stripe pattern abruptly. Then, the X-ray illuminating area of FeBO3 (4 4 4) reflection increases considerably (see Fig. 3(c)–(e)). From the histogram of a dashed line part of Fig. 3(e), the distance between the nodes of magnetoacoustic standing wave was estimated to be 290 lm quantitatively (see Fig. 3(f)). These results imply that rf magnetic field over 8.4 Oe excites the acoustic standing wave in FeBO3 crystal, and it causes a striped deformation for FeBO3 crystal through magnetostrictive interaction [8]. As a noticeable effect, the excited magnetoacoustic standing wave repairs the collapse of the rocking curve due to the congenital defects of this FeBO3 single crystal. It may be a very important phenomenon for the futureÕs application researches. 3.3. Rocking curve of FeBO3 single crystal in Hrf , with Hc 6¼ 0 Secondly, in order to investigate the influence of static magnetic field on the magnetoacoustic standing wave of FeBO3 crystal, rocking curves of FeBO3 (4 4 4) reflection were measured with various strengths of static magnetic field; (Hc ¼ 0, 3, 6, 12, 25 Oe). The rocking curves are shown in Fig. 4. (In these measurements, the peak amplitude of rf magnetic field was fixed in 16.8 Oe.) As is shown in Fig. 4(a) and (b), at the strength of static magnetic field below 3.0 Oe, the measured rocking curves did not show noticeable changes, and they kept a sharp form of single-peak except for the slight broadening of FWHM (<2.0 arcs). However, at the strength of static magnetic field over 6.0 Oe, the rocking curve shows a strong broadening of FWHM and peak splitting abruptly. At the same time, the peak intensity shows a strong reduction
Fig. 4. Rocking curve of FeBO3 (4 4 4) reflaction placed in external magnetic fields; Hrf ¼ 16:8 Oe and Hc : (a) 0.0 Oe, (b) 3.0 Oe, (c) 6.0 Oe, (d) 12.0 Oe, (e) 25.0 Oe.
(see Fig. 4(c)). Finally, through the opposite process of the previous experimental results (see Fig. 2), the rocking curve goes back to the collapsed form of sub-peaks and broad tails (see Fig. 4(d) and (e)). From these results, we found that the static magnetic filed could destroy the sharpness of the rocking curve, which was realized by exposing rf magnetic field, and the noticeable transformation of rocking curve broke out in a specific range of 3.0–6.0 Oe. In the viewpoint of practical applications, this broadening effects is also very interesting as well as narrowing of FWHM. Because, our experimental result indicates that the shape of
T. Mitsui et al. / Nucl. Instr. and Meth. in Phys. Res. B 199 (2003) 75–80
79
Fig. 5. Stroboscopic topographs of FeBO3 (4 4 4) reflection placed in rf magnetic field and static magnetic fields. All topographs are recorded at peak angles of rocking curves of Fig. 4(a)–(d). Fig. 5(e) is the histogram as a function of the X coordinate on the topograph of Fig. 5(b).
rocking curve of FeBO3 crystal can be controlled by only an weak static magnetic field; Hc < 12 Oe. For example, this property may realize a function of X-ray optical shutter element. 3.4. Strobo X-ray topography of FeBO3 single crystal in Hrf with Hc 6¼ 0 The interrelation between broadening of FWHM and magnetoacoustic standing wave of FeBO3 crystal was investigated by stroboscopic Xray topography. The topographs were recorded at the peak positions of each rocking curves of Fig. 4(a)–(d) and they are shown in Fig. 5(a)–(d) re-
spectively. As is shown in Fig. 5(a) and (b), both topographs of single-peak cases show the periodic black-and-white stripe patterns. But, from the histogram of a dashed line part of Fig. 5(b), the distance between the nodes of magnetoacoustic standing wave is about 170 lm (see Fig. 5(e)). That value is short in comparing with the case of Hrf and Hc ¼ 0 Oe (see Fig. 3(e)), and it demonstrates that the applying of weak static magnetic field of merely 3.0 Oe affects the magnetoacoustic vibrating mode of FeBO3 crystal very sensitively. On the contrary, the topographs of sub-peaks cases recorded with the static magnetic field over 6.0 Oe show the completely disappearance of the
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T. Mitsui et al. / Nucl. Instr. and Meth. in Phys. Res. B 199 (2003) 75–80
magnetoacoustic standing wave (see Fig. 4(c) and (d)), and the X-ray diffraction contrasts change into a uniform illuminations from small areas of FeBO3 crystal surface by the regeneration of misorientations and bent. From the results of rocking curve and stroboscopic topographs, we can draw the conclusion that the disappearance of magnetoacoustic standing wave is connected to the broadening of FWHM.
standing wave of FeBO3 crystal play an important key role in the narrowing and the broadening of FWHM respectively.
Acknowledgements The authors are grateful to H. Takei for the FeBO3 single crystal, Y. Yoda and X.W. Zhang for fruitful discussions and T. Harami for a critical reading of the manuscript.
4. Summary To sum up, stroboscopic double crystal X-ray topography is a very suitable method for magnetoacoustic vibration of FeBO3 crystal. This method gives us many fruitful informations. In our cases, the rocking curves of FeBO3 (4 4 4) reflection showed that the extreme narrowing of FWHM took place at the strength of rf magnetic field over 8.4 Oe. On the contrary, the additional static magnetic field over 6.0 Oe led to the strong broadening of FWHM. In addition, the recorded stroboscopic topographs visualized the excited magnetoacoustic standing wave of FeBO3 crystal. As the results, we found that emergence and extinction of magnetoacoustic
References [1] M. Eibsch€ utz, M.E. Lines, Phys. Rev. B 7 (1973) 4907. [2] M. Pernet, D. Elmaleh, J.C. Joubert, Solid State Commun. 8 (1970) 1593. [3] R. Diehl, Solid State Commun. 17 (1975) 743. [4] M.V. Chetkin, V.V. Lykov, JETP Lett. 52 (1990) 235. [5] L.E. Svistov, V.L. Safonov, L. L€ ow, H. Benner, J. Phys.: Condens. Matt. 6 (1994) 8051. [6] Q.Z. Zhang, M. Mino, V.L. Safonov, H. Yamazaki, J. Phys. Soc. Jpn. 69 (2000) 41. [7] V.I. Ozhogin, V.L. Preobrazhenskii, USP Fiz. Nauk. 155 (1988) 539 (Sov. Phys. USP 31 (1988) 713). [8] L. Matsouli, V. Kvardakov, J. Espeso, L. Chabert, J. Baruchel, J. Phys. D: Appl. Phys. 31 (1998) 1478.