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Fabrication and Investigation of Rare-Earth Oxide Thin Films Sandwiched Complexes

Thesis Info

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Author

Ismail, Muhammad

Program

PhD

Institute

Bahauddin Zakariya University

City

Multan

Province

KPK

Country

Pakistan

Thesis Completing Year

2016

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/7527/1/Muhammad_Ismail_Physics_2016_BZU_Multan_05.05.2016.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726188154

Similar


This dissertation reports the fabrication and characterization of CeO2 based nonvolatile memory devices as metal/insulator/metal structures. The RRAM devices have been deposited under various deposition conditions using different electrodes, with different stack morphology and various thicknesses of active CeO2 layers. In the case of Zr/CeOx/Pt devices a forming-free bipolar resistive switching has been observed. HRTEM and EDX studies have indicated the formation of a ZrOy layer at the Zr/CeOx interface. The observed resistive switching has been suggested to be linked with the formation and rupture of conductive filaments constituted by oxygen vacancies. The presence of oxygen vacancies has been noticed through XRD and confirmed by EDX in the nano-polycrystalline CeOx film and in the nonstoichiometric ZrOy interfacial layer. Similar results have been observed for the resistive switching characteristics of Pt/CeOx/TiN devices as confirmed by XPS, but in this case, the observed resistive switching behavior can be attributed to an interfacial layer TiON, as determined by HRTEM image. That is why this device exhibits low operation current (100 μA), high ON/OFF resistance ratio (>105) and good retention both at room temperature and at 85 °C. More interestingly, the TaN/CeOx/Pt based devices exhibited bipolar resistive switching even without any requirement of electroforming step. For these devices, TaON interlayer, as verified by HRTEM and XRD, has been suggested to play the main role in the resistive switching mechanism which stems from connection and disconnection of filamentary paths made of oxygen vacancies. On inserting an ultrathin metallic layer in Ti/CeO2/Al/CeO2/Pt stack, the resultant device has demonstrated dual resistive switching behaviour. These devices could switch between the two operating modes merely by choosing the polarity of RESET voltage. In addition, the requirement of identical current compliance during the SET process of both xxvii modes provides an additional advantage of simplicity in device operation. On the basis of analyses of current–voltage characteristics and temperature dependence of resistance, resistive switching mechanism has been proposed to be originated from a combined effect of field induced diffusion of oxygen and Al ions in the sandwiched ceria matrix. Without metallic insertion, bilayer Ti/CeO2-x:CeO2/ITO memory stacks have demonstrated stable bipolar resistive switching behavior with low-voltage operation and good endurance. In addition, the narrow cycle-to-cycle and device-to-device distributions of resistance switching parameters have been proposed to originate from the electric field induced drift of defects preferably along grain boundaries in the bilayer structure of ceria. On using both electrodes of conducting oxide (instead of metals), fully transparent (with >80% optical transmission) RRAM devices in ITO/CeO2/ITO format (with weak polycrystalline CeO2 phase) have been found to exhibit reliable bipolar switching behavior. The dual role of ITO polycrystalline films as defects reservoir as well as source of O2- ions in these devices becomes the cause of good data retention (over 104 s) and reliable performance both at room temperature and 85 oC. In almost all the devices studied in this PhD work, Ohmic and Poole Frenkel conduction mechanisms are found to be responsible for charge transport in the low- and high-resistance states respectively. The observed RS characteristics and performance of various CeO2-based devices have shown their potential as candidates for future non-volatile memory applications.
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انجمن پنجاب

تعارف:
اس انجمن کا پورا نام "انجمن اشاعت مطالب مفیدہ پنجاب" ہے یہ انجمن لاہور میں جنوری 1865 میں قائم ہوئی۔ محمدحسین آزاد اور ڈاکٹر لائٹنر نے کوششیں کی۔محمد حسین آزاد نے اپنے کچھ جدید اور اہم نظریات کو عملی صورت دینے کے لئے اس انجمن کو استعمال کیا اور اس سے لوگوں میں ایک فعال ادبی تحریک پیدا کی۔
انجمن پنجاب کے مقاصد:
انجمن پنجاب کے درجہ ذیل مقاصد تھے:
1 :قدیم مشرقی علوم کا احیائ۔
2 : صعنت و تجارت کا فروغ ۔
3: کے لوگوں میں دیسی زبان کے ذریعے علوم مفیدہ کی اشاعت کرنا ۔
4: علمی و ادبی ،معاشرتی اور سیاسی مسائل پر بحث کرنا۔
5:صوبے کے بارسوخ اہل علم طبقات اور افسران حکومت میں رابطہ قائم کرنا۔
6: پنجاب اور ہندوستان کے دوسرے فرقوں کے ساتھ روابط اور تعلقات کی مضبوطی۔
ادبی خدمات
محمد حسین آزاد اس انجمن کے روح رواں تھے اس انجمن سے پہلے مشاعرے کی روایت موجود تھی لیکن وہ روایت طرحی غزلوں کی تھی اس انجمن نے نئی طرح کے مشاعرے شروع کئے یعنی مختلف موضوعات پر نظمیں کہی جاتی تھیں ہر مشاعرے میں ایک موضوع دے دیا جاتا تھا جس پر مختلف شعراء لکھ کر لے آتے تھے اس لحاظ سے اس انجمن نے مشاعروں کی طرز میں ایک نیا رجحان پیدا کیا ان مشاعروں میں نظمیں پڑھی جاتی تھیں اس لیے ان کو مناظموں کا نام دیا گیا۔
موضوعی نظم لکھنے کا رجحان:
موضوعی نظم لکھنے کا اولین تجربہ آزاد نے نہیں کیا بلکہ اس سے پہلے زمانہ قدیم میں اس کی روایت موجود تھی مثلا سلطان محمد قلی قطب شاہ کی کلیات میں نظمیں ہیں اس کے علاوہ دکنی دور میں مثنویاں بھی لکھی گئیں۔جو نظم ہی کا ایک حصہ ہیں اس کے علاوہ نظیر اکبر آبادی نظم روایت میں بہت بڑے شاعر ہیں۔ان...

مظاهر الرحمة في شخصية الرسول

Those who abused the Prophet r, and accused him of violence, slander and falsely, had never listened to the call of the mind. They should never ignore the one of the most important verses of the holy book revealed from the Creator, Allah Almighty, that Prophet Muhammad r has been sent to the mankind purely for offering mercy. How can they neglect the fact that the Prophet r himself said if he was a leader without mercy, people around him did not accompany him. When we study the life of Prophet r, we observe that all factions of the society, whether they are slaves or independent, Muslims or non- Muslims, men or women, beloved friends or worst enemies; they were behaved not only with extreme justice, but with utmost mercy. So we find that it was a mercy in everything, in education, in advocacy and in legislation, in war and peace, in the family and society, and in all walks of life, etc. In this article, aspect of mercy in the personality of holy Prophet Muhammad r has been discussed in detail. Opinions of the Orientalists are also presented in the article. Aspect of mercy was not only an ingredient of the personality of Prophet r, but He r also made mercy a part of his followers’ personalities. So history witnesses that there was an elongated reign of peace in the world, whenever Muslim Rulers were in power.

Synthesis and Characterization of Chitosan Based Biocompatible Polyurethanes

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