The primary aim of this work was to synthesize and develop intrinsic ferromagnetism at or above room temperature in transition metals doped ZnO nanoparticles and to correlate the structural and magnetic interaction with a view to understanding the origin of ferromagnetic ordering in these nanoparticles. The synthesis process was optimized for preparing nanomaterials to be studied and then crystallized via annealing process at elevated temperature in various atmospheres viz. ambient, forming gas (gaseous mixture of argon (95%) and hydrogen (5%) and oxygen. The effect of annealing on different environments of the samples has been explored. The materials studied include; Zn1-xCoxO (0.00≤x≤0.10), Zn1-x-yCuyCoxO (x = 4%, 0.5% and 0.00≤ y<0.01), Zn0.96-xCo0.04MnxO (0.00≤x≤0.02) and Zn0.96- xCoxMn0.04O (0.00≤x≤0.02). The structural studies via X-ray diffraction show single phase character of Zn1-xCoxO (0.00≤x≤0.10) nanoparticles which are seen to be paramagnetic when annealed in air and become ferromagnetic on annealing in a reducing atmosphere. Electronic characterizations (via XPS) revealed Co ions are in +2 valance state and replaced with Zn ion on the ZnO lattice. The energy band gap of these compositions has been studied via diffuse reflectance spectroscopy (DRS) and found to decrease with Co addition. Optical studies also confirm the presence of Co +2 in substitutional sites. Magnetic studies, correlated with the XPS, clearly suggest that ferromagnetism occurs in the Co dopes samples with the introduction of oxygen vacancies generated by annealing in a reducing atmosphere. Resistivity studies shows a corresponding trend viz. reducing atmosphere increases the conductivity very significantly in the ferromagnetic compositions. The ferromagnetic samples exhibit an apparent change from insulator to metal with increasing temperatures for T>380K and this change along with the magnetic and electrical transport properties were observed to be reversible. The effect of a non-magnetic co-dopant such as Cu ions (concentration <1%) was studied in detail and in these low (Cu) dopant compositions the moment displays a non-monotonic variation with Cu concentration. The XPS of Cu 2p core spectra revealed that ionic state of Cu begins to include the +1 state in addition to the dominant +2 state with increasing Cu concentration. This change correlates with what we interpret as a strong decrease in the concentration of oxygen vacancies and the decrease of the ferromagnetic moment Therefore the effect of Cu at lowconcentrations appears to be indirect; via increasing or decreasing the oxygen vacancies whose role appears to be critical in this context. Furthermore, the effect on the ferromagnetism of this system (ZnO) has been investigated with Mn and Co ions as magnetic co-dopants in an n-type environment. We find that while a purely Mn doped sample exhibits weak ferromagnetism at room temperature, the general effect of Mn as a co-dopant with Co, in an n-type environment, is to decrease the moment strongly. All of our results can be systematically explained within the context of defect mediated ferromagnetism in these wide band gap semiconductors where the coincidence of the spin split impurity (defect) band states and the 3-d states leads to the development of a net moment alongside the formation of spin polarons. The nanoparticle nature of the materials may serve to enhance the density of states and leading to a fulfillment of the Stoner criterion fro ferromagnetism. Thus central to the ferromagnetism in these doped semiconductor nanoparticles is the role of the oxygen vacancies as n-type defects and the states they create within the band gap, with the transition metal ions serving to provide the electrons that fix the position of the Fermi level.
ریاست کا عزم: فرقہ واریت اورمتشد در ویوں کا خاتمہ ریاست کا وجودعوام النّاس کے لیے ایک نعمت سے کم نہیں ہوتا، ریاست میں موجود ارباب حل و عقد ر یاست کے جملہ امور اگر اسلامی خطوط پر چلانے کے خواہشمند ہوں تو ریاست واقعی انعام خداوندی ہے۔ اگر ریاست کے ارباب بست و کشاد کے اذہان مفلوج ہو چکے ہوں تو پھر ان سے فلاح و بہبود کی توقع عبث ہے۔ فرقہ واریت ایک ناسور ہے جو معاشرے کے حسن کو گہنا رہا ہے۔ ایک مردار ہے جس کے تعفن سے حیات کا وجود ختم ہوتا ہوا نظر آرہا ہے۔ ایک خدا، ایک رسول صلی اللہ علیہ و آلہٖ وسلم اور ایک قرآن کے ماننے والے جب آپس میں دست و گریباں ہوں، جب نورو ظلمات کی تصویر پیش کررہے ہوں، جب دھواں اور سائے کا تصور پیش کر رہے ہوں، جب پھول اور کانٹے کا نمونہ پیش کر رہے ہوں ، تو پھر اس رنگ و روغن سے بنی ہوئی معاشرے کی تصویر کبھی بھی اسلامی معاشرہ کہلانے کی روادار نہیں۔ فرقہ بندی ہے کہیں اور کہیں ذاتیں ہیں کیا زمانے میں پنپنے کی یہی باتیں ہیں فرقہ واریت کا خاتمہ صرف اس صورت ممکن ہے کہ قوت ِبرداشت کا عملی مظاہرہ کیا جائے، انسانیت سے پیار کیا جائے اگرکسی کے نظریات میں تفاوت موجود ہے تو بطریقہ احسن اس کی رہنمائی کی جائے۔ اور یہ کام ریاست بدرجہ اتم کرسکتی ہے۔ بشرطیکہ وہ اس میں مخلص ہوتعلیمی نصاب میں تبدیلی سے بھی منزل حاصل کی جاسکتی ہے۔ اوّل سے لے کر ایم۔ اے لیول تک فرقہ واریت والے مضمون شامل نہ کیے جائیں خطیب چونکہ اپنے مافی الضمیر کے اظہار کے اچھے مواقع کا حامل ہوتا ہے وہ بھی اپنی نجی محفلوں میںفرقہ واریت کے نقصانات پر واضح روشنی ڈال سکتا ہے۔...
The use of similes, metaphors, proverbs and idioms is given its due prestige in the annals of literature. To mention their use in the Islamic literature especially in the sayings of our Holy Prophet (PBUH) renders an ease and comfort in order to elaborate upon the Islamic teachings. It not only enhances interest but renders an inexplicable charm to explicate Islamic teachings so as to make them easy to comprehend. The use of figurative language enhances the rhythmic flow and charm of language and thus brings in a huge impact on literature. It is in this way that the proselytization task be done in an easy effective manners.
Assuming no essential difference between bilingual and monolingual linguistic capacity, the present study offers a Null Theory of intra-sentential CS in terms of Chomsky’s (2000, 2001 and 2008) phase theory with negative and positive evidence from Urdu/English code-switching. The inability of the existing CS-models in accounting for the recurring switches in the data necessitates the minimalist account of CS offered in the study. It is proposed that both mixed and unmixed sentences are derived in a similar fashion in two distinct derivational chunks called Phases. Since one phase does not remain accessible to the other due to Phase Impenetrability Condition, switches in each phase are determined independently of each other. As locus of parametric variation, v plays crucial role in the interaction between two distinct grammatical systems. As documented in the data, selection of v from one lexicon precludes the selection of T and D from the opposite lexicon due to a mismatch in their feature specifications; however, C, being phase head itself remains out of the control of v, and therefore, may be contributed by either of the lexicons subject to its compatibility with its complement TP. Adopting ‘root’ view of lexical categories, it is argued that lexical categories being unspecified roots may be supplied by either of the lexicons randomly; however, selection of functional categories is subject to their correspondence to the feature specifications of v. The difference in switching behavior of adjunct and complement projections also stems from their different structural relation to v. It is further posited that it is v instead of lexical head or head-parameter which determines the word-order of the constituents. It is concluded that all mixed and unmixed derivations including the switches involving different heads and complements adhere to a general condition of well-formedness which restricts any conflict in feature specifications of the syntactic objects involved in a derivation; hence no CS-specific postulates required to account for CS-data.