This thesis constitutes a series of studies on the effects of divalent dopants (A) in place of Bi in the BiFeO 3 (BFO) multiferroic systems. In addition the effect of film thickness on the multiferroic properties of BFO has also been investigated. The studies include a complete set of structural, electronic, magnetic, optical and dielectric studies on the Bi 1- x Sr x FeO 3-δ (0 ≤ x ≤ 0.45) and Bi 0.75 A 0.25 FeO 3 (A = Pb, Ba) systems. The studies have been carried out with the knowledge that substitution of trivalent Bi with the respective divalent ions will induce changes in the crystalline as well as electronic structures which in turn would affect the multiferroic properties of the system. Accordingly we find that in contrast to the weak ferromagnetism of the parent material each of the x=0.25 doped systems exhibits ferromagnetism at room temperature. A strong correlation is observed between the magnetic and structural properties, e.g. in the case of Sr doped BFO there is a strong enhancement of ferromagnetism between x=0.15 and x=0.25 that coincides with a structural transition from rhombohedral to cubic phase (R3c → Pm-3m) at x=0.25. Magnetic moment was observed to increase with increase in the radius of A-site ion being largest for the Ba doped system. Further insight into the origins of the ferromagnetism enhancement was obtained through Mössbauer measurements which showed that despite being doped with a divalent ion, the Fe ions in BFO retained their trivalent state. We find that A 2+ ion substitution at Bi 3+ site results in oxygen deficiency and consequently in a tetrahedral coordination for some of the Fe−O ions. The role of oxygen vacancies in promoting ferromagnetism was evident from the decrease in ferromagnetic moment in oxygen annealed samples. Thus the ferromagnetism in these systems is correlated with the structural transformation at x=0.25 which tends to destroy/weaken the parent antiferromagnetic cycloidal spin structure while induced changes in the superexchange interactions, due to size differences and oxygen vacancy effects, also contribute to the observed differences. We find a systematic but anomalous decrease in the magnetic coercivity at low temperatures which is explained in terms of an effective magnetic anisotropy that includes the effects of magnetoelectric coupling. The dielectric response for these doped systems depends in general on the structural details as well as the presence of oxygen vacancies. The Sr x=0.45 composition shows a marked anomaly in ε(T) which is explained in terms of relaxation effects originating presumably in nanoscale polar inhomogeneities. The lone pair substituent Pb leads to the largest dielectric | ixconstant, enhanced magnetization, and large effects on the low-temperature magnetic hysteresis. The optical response of multiferroic Bi 1-x Sr x FeO 3 (0 ≤ x ≤ 0.45) samples is studied in the spectral range from 1 eV to 4 eV by means of UV/Vis spectrometry. Optical response in the studied spectral range was dominated by two charge transfer transitions and two doubly degenerate d-d transitions for all samples. The d-d transitions weakened as the Sr content was increased which is attributed to the transformation of the crystal structure from rhombohedral to cubic. A red shift in the d-d transition energies was observed with increasing Sr concentration which is related to an increase in the crystal field strength. The direct band gap was found to decrease whereas the indirect band gap decreased as the Sr content is increased from x = 0 to 0.45. The ultimate source of the decrease in the energy band gap values and the observed red shift in the d-d transition energies is ascribed to the chemical pressure induced reduction in unit cell volume. For Ba and Pb doped samples the differences in these optical properties are also consistent with the associated changes in the unit cell volume. BFO thin films with thickness increasing from 40 to 480 nm were successfully grown on LaNiO 3 buffered Pt/Ti/SiO 2 /Si(100) substrate and the effects of thickness evolution on magnetic and ferroelectric properties have been investigated. All the BFO films exhibited weak ferromagnetic response at room temperature and saturation magnetization decreases with increase in film thickness. Well saturated ferroelectric hysteresis loops were obtained for thicker films; however, the leakage current dominated the ferroelectric properties in thinner films. The mechanisms for the evolution of ferromagnetic and ferroelectric characteristics in these films have been discussed.
ڈاکٹر سید عبدالعلی افسوس ہے کہ آج قلم کو ایک ایسی برگزیدہ شخصیت کا ماتم کرنا پڑرہا ہے جو تنہا ایک شخص کا نہیں بلکہ علم و عمل کا ماتم ہے، دین و تقویٰ کا ماتم ہے، اخلاق و شرافت کا ماتم ہے، اس شخصیت کو دنیا ڈاکٹر سید عبدالعلی ناظمِ ندوۃ العلماء کے نام سے جانتی ہے، وہ تنہا ڈاکٹر یا ندوۃ العلماء کے ناظم نہ تھے، بلکہ اس زمانہ میں اپنے اوصاف، خصوصیات اور دینی و اخلاقی کمالات میں یگانہ تھے، ان کا نسبی تعلق مشہور عارف باﷲ حضرت سید شاہ علم اﷲ رحمتہ اﷲ علیہ رائے بریلوی کے خاندان سے تھا جس میں علم و عمل، دین و تقویٰ، فقر و تصوف اور ارشاد و ہدایت کی روایات صدیوں سے چلی آرہی تھیں، حضرت سید احمد شہید رحمتہ اﷲ علیہ اسی دووانِ عالی کے گوہر شب چراغ تھے۔ خاندان کی یہ ساری روایات ڈاکٹر صاحب مرحوم کے حصہ میں آئی تھیں، ان کے والد بزرگوار مولانا حکیم سید عبدالحئی صاحب رحمتہ اﷲ علیہ اپنے زمانہ کے مشہور عالم، نامور طبیب، اہل قلم فاضل اور صاحب زہد و تقویٰ بزرگ تھے، ڈاکٹر عبدالعلی صاحب ان کے خلف الصدق تھے، ان کی ذات قدیم و جدید تعلیم کا سنگم تھی، انہوں نے پہلے عربی اور طب کی تحصیل کی، اس کے بعد انگریزی پڑھی اور ڈاکٹری کی تعلیم حاصل کی، یہ وہ زمانہ تھا جب ڈاکٹروں کی زندگی مغرب زدگی اور انگریزی طرز معاشرت کا نمونہ ہوتی تھی، مگر ڈاکٹر عبدالعلی صاحب کی فطرت ایسی صالح و سلیم تھی اور ان کی رگوں میں ایسے بزرگوں کا خون تھا کہ جدید تعلیم کے مادی اثرات سے ان کا دامن بالکل پاک رہا، حتیٰ کہ ان کی ظاہری وضع قطع بھی خالص اسلامی رہی ناواقف لوگ ان کو دیکھ کر گمان نہیں کرسکتے تھے کہ ان کو...
The formatted initiatives of history of Arabic literature are, as ancient as illiterate era. The age had plenty of almost all literary arts, although it were not in the managed shape like Islamic and mode eras. This age had both the literary arts i.e. poetry and prose. The first one was given full attention for hearing, singing and remembering, while the prose was about to be ignored in these aspects. Despite of done practice, some prosaic arts were orally noted and copied generation to generation. Later on, the arts were put down in their proper chapters with the development of the literature in omade and abase tenures. Some varieties of the prosaic arts are hereby introduced with explanation of its historical background, famous authorities, necessity and samples. This research contains on three sections with research study of three main arts; phrases, golden words and addresses. This research is made in descriptive manner in Urdu language. The purpose is, to make Urdu literates know the limitations of Arabic prosaic arts of illiterate era. Thus, it will be a new addition for Urdu literates and writers.
This dissertation consists of five chapters. In the first chapter, survey of Christian Muslim literature has been presented and different modern trends have been described in a lucid manner. All the relevant sources related to Jesus came under discussion. The major focus was upon the Holy Qur’an, Ahadith and Christian sources. In the second chapter, different issues of controversy between Christianity and Islam are presented and then those are analytically and critically evaluated in a comparative method. To substantiate Islamic viewpoint, frequent evidences have been presented from the Christianity as well. In the third chapter, classical and modern Christian approaches to the life of Jesus have been discussed and presented in an impartial way. A historical evolution in the thought of leading Christian scholars came under discussion. There viewpoints are portrayed as they wanted to be understood without any prejudice and partiality. Fourth chapter deals with Muslim representation of Jesus Christ. Most of the Muslim scholarship presented Islamic understanding of Christianity in general and Jesus Christ in particular. An analysis of classical and modern trends in Muslim thought was the major focus in this chapter. In the fifth chapter, Christological issues in Christian Muslim literature have been identified. Different references have been quoted for the necessity of Dialogue between Christian and Muslim World.. In this chapter, Dialogue has been defined effectively in the light of Muslim & Western scholarship. We have applied comparative method, in a descriptive and analytic way. A code of conduct has been suggested for the Provisions of Interfaith dialogue in Christian Muslim perspective. An attempt has also been made to clarify its scope, methodology and Principles keeping in view the Discourse of Islam and Christianity.