I read much about atoms, molecules and electrons but still i am not able to get answers for my study towards magnetic media. Please help me with the following questions in anyway you can, i would be really really grateful as it is going to help me a lot with my study towards magnetic media.
My knowledge base considering the following questions: Atomic structure, how electrons fill into electron shells following hands rule, only two electrons can exist in an orbital (I am clear with the concept of orbitals as what they are their shapes energy level etc). Only two electrins can exist in an orbital and each of them should have opposite spin. Working of hard disk drives, in terms of its hardware and how the control the read / write head which consists of a coil, BUT i am more confused with what happens to the magnetic media (the magnetic material on the magnetic media) related to electron spins, electrons, flux reversals, etc. I have been coming across the new technology research to control individual electron spins and i have to clear my concepts before i move further.
1. Are electrons freely flaoting in nature / space? Or as soon as they are generated, they try to form atoms, meaning that though there are freely floating electrons in space we can never find out their existence without being in an atom? From where do electrons come from?
2. According to Pauli Exclusion Principle, no two electrons having same spin can exist in the same orbital. If that is the case, then how exactly are molecules formed? Example, hydrogen atom on alone has one electron. What is its electron spin? is it -1/2 for all independent hydrogen atoms or +1/2 for all independent hydrogen atoms or it can be anything by default for each individual hydrogen atom? When a hydrogem atom wants to combine with other hydrogen atom to form a molecule, does it keep searching for another hydrogen atom where the spin of the electron is antiparallel to its existing electron spin or it just searches for another hydrogen atom and automatically reverses the other hydrogen atom's electron spin and gets covalently bonded or it reverses its own electron spin and gets covalently bonded or none of the spin is reversed?
3. Can anyone tell me sharing, pairing, donating, accepting of electrons is related to what kind of bonding? I mean which (or which all) is (are) relating to covalent bonding (i.e. bonding between atoms of same elements)? Which (or which all) is(are) related to bonding of one element with other?
4. After understanding the above doubts spin functionality of an individual hydrogen atom and hydrogen molecule, i have doubt that will an individual hydrogen atom (if it ever exists as an individual atom), will it be affected by the magnetic field? If an hydrogen atom never exists as an individual atom, does the magnetic field have an effect on the molecule of hydrogen?
5. This was all about a hydrogen atom with one valence eletron. What happens in case of other elements, i mean how is electron spin handled when an element's atom has more than one valence electrons? (As i had already asked about how electron spin is handled in case of hydrogen, i will be able to understand how covalent bonding takes place for other atoms) However i dont know if it is separate for other elements compared to hydrogen or covalent bonding takes place in the same way?
6. Why some elements which have valence electrons are magnetic while some are not (even though they also have valence electrons). Does it depend on the number of valence electrons or net valence electron spin or what is it?
7. I know valence electrons in an atom all align in the same direction. How does an external magnetic field affect this alignment? Does an external magnetic field have an effect on individual atom or a molecule or a group of molecules or on what?
8.Again once i now how covalent bonds are formed and how they handle electron spin, I am confused that if during formation of covalent bond the electrons complete the valency deficiency (either by merging with other atoms by modifying the other atoms spin or modifying its own spin or modifying the spin of none), how magnetic field will really affect? If the atoms had covalently bonded by alterating either one atom's spin, are they still aligned all in parallel to the external madgnetic field? By all i mean does this alignment happen for an individual atom or for molecules or how exactly does it happen? If the electrons had altered the spins while covalently bonding, will covalency break when they are again aligned with respect to the external magnetic field?
9.How is the ferromagnetic coating applied on the magnetic media actually working. What is done on this material by the external magnetic field arising from the read write coil head? Is the ferromagnetic material already magnetized when we get a brand new magnetic media. When we say brand new magnetic media, it does not have any data. what do we mean when we say it does not have any data, related to the electron spin of an atom or molecule or what exactly is the condition of the brand new magnetic media?
10. Why indivual magnetic elements are not used as magnetic media, rather alloys are used?
I have been reading a lot through magnetic media finally relating all of them to electron spins and / or alignment, going through terms as flux reversals generation / detection but i have not been able to correlate them exactly and it is really very important for me to understand to proceed with my study with magnetic media.
11. What exactly is done in relation to the electrons or electron spin alignment or what
exactly is done while writing data on magnetic media? (not the mechanical part, only the flux field or flux generation / reversal, read or made and how is all this related to electron spins and their alignment (whether in an atom or molecule or what))?
12. What exactly is done in relation to the electrons or electron spin alignment or what exactly is done while reading data from magnetic media? Is something sensed in relation to electrons or electron spin or their alignment or what is done? How is it done (not the mechanical part, only the flux field or flux generation / reversal, read or made and how is all this related to electron spins and their alignment (whether in an atom or molecule or what))?